Presentations, Images and Visual Communication

A presentation begins with a decision about its viewers. The audience is who will see it. The purpose is what you want those people to know, do or feel afterward. A presentation may inform, explain a process, persuade or entertain; decide which purpose leads.

Turn knowledge about viewers into choices

Ask about viewers' ages, roles and existing knowledge. Find out what they need from the topic and which words they understand. Then connect each answer to a choice. New club members need names and explanations; experienced members may need results and a decision. Plan for low vision, hearing loss, color blindness and reading difficulties from the start.

The setting matters too. In a hall, use large text and simple visuals that people can read from the back. During a live talk, your voice supplies detail. An unattended lobby screen needs enough written information to stand alone, with time to read it. Slides emailed for later reading need fuller explanations than the slides behind a speaker. A tight time limit also limits how many ideas you can develop.

Read a brief as a checklist

A brief describes the job a teacher, client or employer wants. Pull out the audience, purpose, required content, deadline, length, place of use, output format and size limits. Record the house style too: the organization's rules for its logo, colors, fonts and layouts.

Separate requirements from preferences. In "The poster must be A3, include the event date and show our logo," all three details are requirements. "A modern look would be nice" leaves room for judgment. You can check a page's size directly; judging its look needs discussion and a trial with viewers.

Work through an audience change

Imagine preparing a proposal to reduce cafeteria food waste. For 12-year-old classmates, choose everyday words, a relevant photo and one clear number. Explain how students can help. For the school board, use the same accurate facts, but show the cost, four weeks of measurements and the decision you want members to make.

An outline for classmates might end with "Choose a smaller first serving." The board version might end with "Approve a two-week trial." The request changes because the viewers have different powers and needs. A funny phrase that works among friends may confuse board members; replace it with wording they understand.

Check the design against the job

Use the checklist while building, not only at the end. If the brief requires the school logo, a beautiful slide without it still misses a requirement. Apply house style consistently so viewers recognize who is speaking. A small palette and fixed fonts also make later editing easier.

Designing mainly for your own taste can leave viewers behind. Ask a person like your intended viewer to read a sample slide. Notice which words need explaining, whether the main message is clear and whether the requested action is easy to find.

A useful slide sequence leads the audience through a message. Start by deciding what they should understand at the end, then arrange the evidence and explanation that get them there.

Give the talk a beginning, middle and ending

The opening catches attention, names the topic and explains why it matters. The body develops a few main points, usually three to five, with evidence or examples. The conclusion draws those points together and leaves one takeaway or a call to action.

A title slide identifies the topic and presenter. A longer talk may need an agenda so viewers know the route. Sources and image credits belong beside the relevant material or on a clearly organized final slide.

Plan the slides before formatting

An outline lists slide titles and the points beneath them. A storyboard sketches the slides, including where images and text will go, with notes about content and timing. Use the outline to test the argument and the storyboard to test how it will look. Some programs turn top-level outline lines into titles and indented lines into slide bullets.

Give each slide one main message. "Food waste doubled in four weeks" communicates a finding; "Data" only names a topic. Read the titles in order. If the sequence jumps from the problem to an unrelated detail and back, move or remove the detail. Split a slide that carries two separate messages.

Slides shown during a talk hold short phrases, useful images and charts. Keep the full explanation in speech and speaker notes. Putting the script on screen makes the audience read while you speak.

Build a persuasive sequence

For a proposal for recycling bins, plan the route as problem, evidence, solution and action. First show what is being thrown away. Next give a measured bottle count and a supporting photo. Then explain the labeled bins you propose. End with the decision: "Vote yes on Friday." Each slide prepares viewers for the next, and the request follows from the evidence.

Check that a number comes from a real measurement or reliable source. Exaggerating it may make the proposal sound stronger briefly, but it damages trust when checked.

Match the structure to the task

A how-to presentation follows the order of the work. For cropping a photo, show selecting the photo, adjusting its crop and applying the change. Use one step per slide or reveal steps one at a time, so the viewer sees the action currently being explained.

Charts also have different jobs:

Give a chart a clear title, identify categories and series, and include units where needed. Direct labels can replace a separate legend. A pie chart's labeled slices identify its parts without axes.

Rehearse the sequence aloud with a timer. One to two minutes per content slide is a rough planning guide; your actual pace decides the final count. Leave space for the conclusion and questions instead of spending the entire time on the body.

Clear slides help viewers notice the main idea quickly. Design choices work together: the words, their size, the images and the empty space all guide attention.

Use four design principles

Contrast makes important things stand out, such as a large bold title. Alignment places objects along shared edges. Repetition carries the same fonts, colors and layout choices through the presentation. Proximity places related things together, such as a photo and its caption.

Imagine a chart at the left and its explanation far away at the right, beside an unrelated image. Moving the explanation next to the chart makes the relationship clear. Aligning the chart and text with the title gives the slide a visible order. These changes help without adding any decoration.

Visual hierarchy is the order in which the eye notices items. Usually the title comes first, then the main image or chart, followed by supporting text. Make the most important item strongest through size, weight or position. White space separates groups and prevents every item from competing for attention; it is useful space, even when it contains no words.

Choose text people can read

Use one or two font families. Choose a plain font for body text, keep it large and leave room between lines. For slides shown in a room, 36–44 pt titles and body text of at least 24 pt are common starting guidelines. Check the slide from a distance because the room, screen and viewers affect readability.

Bullet points should be short phrases. About six bullets of six words each is a rough limit, not a target to fill. A process with three steps needs three clear steps. Move a long explanation into your notes or divide separate ideas across slides. Avoid long passages in capitals or italics.

Make color and images earn their space

Choose a small palette, such as two main colors and one accent, based on the house style. Text and background need a clear difference in lightness. Yellow on white is difficult to read. Text over a busy photo can disappear among the details; place a solid band behind it or choose a quieter area.

Use an image because it explains or supports the message. Give it enough room to be understood and use enough pixels for its display size. Preserve its proportions when resizing. Several tiny decorative images can make the slide harder to follow than one relevant photograph.

Improve a crowded slide

A recycling slide starts with eight long sentences, small red text on green and a stretched cartoon. First decide its message: "Recycling saves our school money." Keep three short supporting points. Use 28 pt dark gray text on white. Replace the distorted cartoon with a large photo of the bins, cropped without stretching, and place its caption nearby.

A theme supplies coordinated colors, fonts and effects. A template is a starting file that can store a theme, layouts and sample slides. A suitable template helps apply house style, but you still need to remove clutter and check that each image and word supports the message.

A presentation is easier to update when its shared design is stored in one place. The slide master controls the background, text styles, colors and placeholder positions of slides based on it.

Separate the master, layout and content

The master supplies shared design. Layouts arrange spaces for particular slide jobs, such as title, title and content, two content areas or a section heading. Placeholders are the reserved boxes in those layouts for titles, text, pictures and charts.

Choose a layout that fits the content, then fill its placeholders. This keeps placement consistent and helps the software understand the slide. A title in the title placeholder appears in outline and navigation views and is available to screen readers. A text box drawn at the top may look like a title without carrying that role.

Set up a club presentation

Suppose a club wants its logo at the top right, dark-blue 40 pt titles, 24 pt body text and slide numbers at the bottom right.

1. Open the master view and select the master used by the slides.
2. Place the logo once at the required position.
3. Format the title and body placeholders, including bullet styles.
4. Enable the footer and automatic slide numbers in the appropriate settings.
5. Close master view and create slides from the matching layouts.

Now the logo remains in the same place without repeated pasting. When the club changes its main color, update the shared design once. Review the slides afterward to check how that change fits their content.

Know what a local change does

Direct formatting on a slide can override the master. That is useful when a particular item needs special treatment, but a series of local font changes can leave the presentation inconsistent. If every title needs a new color, change the master instead of editing titles individually. If one slide does not follow, check for a direct override and restore the shared formatting.

Automatic slide numbers also save work. They update when slides move, are inserted or are deleted. A number typed into an ordinary text box remains the same, even when it becomes wrong.

Organize the sequence

Insert new slides with the right layout. Duplicate a slide when its arrangement is useful again, then replace its content and give it a distinct title. Change an existing slide's layout when its content changes. Delete slides that no longer help the message, and reorder the remainder in the thumbnail pane or slide sorter.

After moving or duplicating slides, read the titles in order. Check that the sequence still makes sense and that automatic numbers follow it. Copying a logo onto every slide creates more work and slight position differences; storing it on the master prevents both problems.

Images, charts, clips and links should help the audience understand or act. Choose each object for a job, then check how it behaves during the show.

Arrange objects accurately

A slide can hold text, pictures, shapes, arrows, symbols, callouts, tables, charts, audio and video. Use alignment guides, gridlines or exact position and size values to place them. A callout might point to a part of a diagram; a table might let viewers compare a few values.

Stacking commands control overlap. Bring to front places an object above all the others; bring forward moves it one level. Send to back and send backward move it the opposite way. If a rectangle covers a caption, change the order so the caption is visible. Grouping lets several objects move and resize together. Ungroup them to edit individual parts.

Choose how media is stored

An embedded clip is stored inside the presentation. This increases the presentation's size but keeps the clip with the slides. A linked clip remains a separate file; playback depends on the expected file location being available.

For example, a video linked from a removable drive may play while that drive is connected and fail on another computer. Embed the clip, or copy and maintain the linked files with the presentation. Test on the actual presenting computer. Set playback to start on a click or automatically, and check any trimmed start and end points.

Build navigation with links

A hyperlink opens a destination: another slide, a file, a web page or an email message. Give it descriptive text, such as "Club registration form," so viewers know what it opens. A working web link also needs the network connection at presentation time.

An action button is a prepared shape with an assigned action, such as next slide, previous slide or a jump to a chosen slide. These features allow a menu or quiz to follow different routes. For a topic menu, link each topic to its slide and add a clear way back. Test every route in slide-show view, including returns and links from duplicated slides.

Distinguish transitions and animations

A transition occurs between slides. An animation changes an object within a slide: it may enter, be emphasized, leave or follow a motion path. Use one subtle transition consistently. Use animation to control attention when it helps the explanation.

For a three-step instruction, set the same entrance effect on each step. Order them step 1, step 2 and step 3, starting each on a click. Run the slide and confirm that each click reveals the next instruction. Adding unrelated effects or transition sounds draws attention away from the process.

A hidden slide stays in the file but is skipped in the normal show. Keep detailed backup evidence there when it may help answer a question. Hiding is a presentation choice, not removal: check what is included when exporting or printing the file.

A finished file still needs a delivery plan. Prepare what the speaker sees, how slides advance and what viewers receive afterward.

Use notes and presenter view

Speaker notes belong to individual slides and hold prompts, extra facts and wording you want to remember. Presenter view can show the current slide, the next slide, notes and a timer on the speaker's screen while the audience sees the current slide. Test the display setup before the audience arrives so private notes stay on your screen.

Rehearse aloud with a timer. Reading silently gives a poor measure of speaking time. Use the notes as prompts, face the audience, speak clearly and leave time for questions. Keep a backup copy of the file and a PDF in another place in case the main copy or software is unavailable.

Set the advancement mode

In a presenter-controlled show, the speaker advances slides by clicking or pressing a key. This allows time for explanation and questions. A self-running show advances using stored timings and can loop after its final slide.

For a lobby display with 8 slides at 15 seconds each:

The loop lasts 2 minutes. Set a time for every slide and enable looping until the show is stopped. Watch a complete cycle. People may arrive halfway through, so each slide must make sense alone and remain visible long enough to read.

Print for the reader's purpose

For 12 slides, six slides per handout page gives two pages per person. Full-page printing gives 12 pages. For a count that does not divide evenly, allow another page for the remaining slides. Check the print preview, including whether hidden slides or notes are included.

Share the right file

Keep an editable original in the program's format, such as .pptx or .odp. It preserves features for later changes. Online tools store editable work in the cloud and can download copies. PDF preserves a fixed reading layout and is useful across devices, but usually loses animation, transitions and playable media. Use a video export when the intended result is timed playback, then check it plays as expected.

Before sharing, proofread names, dates and numbers. Copy required wording and capitalization exactly. Run the accessibility checker, check fonts and linked files, and remove private comments. Compress oversized images if needed, then reopen the shared version. Sending readers the editable file can cause layout changes if their fonts or software differ; a checked PDF is often the clearer reading copy.

Digital pictures store information in different ways. Understanding that information helps you predict whether an image will stay sharp, print clearly and take up much storage.

Compare pixels and shapes

A bitmap, or raster image, stores a grid of pixels, each with a color. Camera photos are bitmaps. A vector image describes points, lines, curves and fills mathematically. Logos, diagrams and icons often suit vectors.

Enlarging a bitmap spreads its existing pixels over a larger area. Edges can become soft or visibly blocky. A vector redraws its shapes at the new size, keeping their edges sharp. Detailed photos suit bitmaps because they contain many small color changes, not just a set of simple shapes.

Pixel dimensions give width and height in pixels. A 4000 × 3000 photo holds 12,000,000 pixels, or 12 megapixels. For a screen, check those dimensions against the size at which the picture will be displayed.

Connect pixels to print size

Pixels per inch, or ppi, tells you how many image pixels fit along each printed inch. A common photo-printing target is 300 ppi. Calculate each dimension separately:

A 4000 × 3000 image at 300 ppi prints about 13.3 × 10 inches. To work in the other direction, multiply physical size by ppi. A 6 × 4 inch print at 300 ppi needs 1800 × 1200 pixels.

A 1200 × 800 image at 300 ppi prints only about 4 × 2.7 inches. Making the print larger spreads the same pixels farther apart and lowers the ppi. Dpi describes a printer's ink dots per inch, a different measurement; clarify what a print shop means when it asks for "dpi."

Do not confuse a setting with new detail

Changing only the ppi setting leaves the pixel dimensions unchanged. It changes the intended print size, not the picture's captured detail or its screen sharpness. Resampling changes the number of pixels. Upscaling adds estimated pixels but cannot recover real detail that was never captured. For a large print, start with enough original pixels.

Explain color depth and color models

Color depth is the number of bits used per pixel. More bits allow more possible colors and increase the uncompressed storage needed.

In 24-bit RGB, red, green and blue each use 8 bits. RGB combines red, green and blue light on screens. CMYK uses cyan, magenta, yellow and black inks for printing. Some bright screen colors cannot be matched exactly in ink, so the printed result may look duller. Ask the print shop which color mode it expects and use a proof to judge the result.

Choose a file format by what the image contains and where it will be used. The smallest possible file is useful only if it still keeps the features and quality the job needs.

Match formats to images

JPEG supports millions of colors but can leave artifacts, such as fuzzy edges around text. A transparent logo saved as JPEG gains a solid background. PNG preserves sharp text and partly transparent edges, though photos are often larger than JPEG versions.

Phone photos may use HEIC. RAW files hold camera data needing conversion for most uses. Drawing and image-editing working formats, such as .psd and .xcf, keep layers and editable text. PDF and EPS can hold vector content. Generic formats such as JPEG, PNG, PDF, TXT, CSV and RTF allow exchange across many programs; a program's own format preserves its particular editing features.

Distinguish kinds of compression

Lossless compression allows the stored data to be rebuilt exactly. PNG, GIF and ZIP use it. GIF preserves its stored palette data exactly, but its color limit can make photographs show bands of color. Lossy compression, used by JPEG and some WebP files, discards image detail. A smaller export may show more artifacts, and discarded detail cannot be recovered from that file.

ZIP and RAR archives can bundle several files for sending or storage. Repeated JPEG editing and saving can cause further loss, so keep a working original and export the final sharing copy from it. Renaming an extension does not convert the data: use an export or conversion command.

Calculate raw pixel storage

For an uncompressed bitmap's pixel data:

At 24-bit color, each pixel needs 3 bytes. A 1920 × 1080 image therefore needs 6,220,800 bytes, about 6.2 MB. Here 1 MB is 1,000,000 bytes.

Halve both dimensions to 960 × 540 and the pixel count becomes one quarter. The data needs 1,555,200 bytes, about 1.6 MB. Keep the original dimensions but use 8-bit color and the data needs one third as much: 2,073,600 bytes, about 2.1 MB. These are pixel-data calculations, not predictions of a compressed file's exact size.

Reduce size without losing the purpose

Reduce dimensions to the display need, choose an appropriate format and adjust export quality. Lower color depth only when the image can tolerate fewer colors. Presentation software can compress pictures and permanently remove cropped-away portions; retain an original first. Check the exported file's actual size and appearance, including text edges and transparent areas.

Changing an image's frame is different from changing its scale. Use the right operation so the subject keeps its natural shape and enough detail for the finished work.

Crop the frame

Cropping removes the outer parts of an image. It can remove clutter, focus on a subject or change the frame's shape. In an image editor, a crop reduces the pixel dimensions without adding new detail. Check the subject's edges before accepting it: a close crop can accidentally remove a head, hand or important label.

For composition, imagine two horizontal and two vertical lines dividing the picture into nine equal areas. Placing a subject on these lines or their crossings is the rule of thirds, a useful guide. Leave space in the direction a person faces or moves.

Resize without distortion

Aspect ratio is width compared with height. A 4000 × 3000 picture has a 4:3 ratio. A 1920 × 1080 slide is 16:9, and a square is 1:1. Lock the aspect ratio when resizing so width and height change by the same factor.

To reduce a 4000 × 3000 image to 1200 pixels wide:

The result is 1200 × 900. Changing only its width would squash the subject. To fit a different frame, crop to that ratio, then resize.

Fit a 4:3 photo to a 16:9 frame

Keep the width at 4000 pixels and find the matching 16:9 height:

Crop from 3000 to 2250 pixels high, removing 750 rows in total. Removing 375 from each edge is one possible centered crop; moving the frame may protect the subject better. Resize the cropped image to the final slide dimensions with proportions locked.

Dragging a photo smaller on a slide often changes only its displayed size. The original pixels can remain inside the presentation. Resizing in an image editor resamples the pixel grid, so reducing dimensions can reduce file size. Enlarging that grid creates estimated pixels, not newly captured detail.

Turn or mirror the picture

Rotation turns an image, perhaps by 90° to correct orientation or by a small amount to straighten a horizon. A small rotation leaves empty corners, which need cropping. Flipping mirrors the image horizontally or vertically. A horizontal flip reverses left and right and makes photographed writing backward. It is different from a 180° turn; flipping both horizontally and vertically gives the same orientation as that turn.

Use exact width, height and position values when a brief specifies placement. Alignment tools help images share edges. In a document, text wrapping controls whether words flow beside an image or stay above and below it. After placement, inspect the image at its final size for distortion, blur and an awkward crop.

Image adjustments solve different problems. Identify the problem first, make a small change and compare it with the original before adding another edit.

Control light and dark

Brightness makes an image lighter or darker. Contrast changes the difference between light and dark areas. More contrast makes darks darker and lights lighter; reducing it can make a picture look flat. Excessive adjustments can turn textured shadows into solid black or bright fabric into featureless white.

Levels and curves provide finer control over shadows, midtones and highlights. They help when one part of the tonal range needs changing more than another. If a face is in shadow but the sky already looks right, select the face and adjust that area instead of brightening everything.

Correct and change color

White balance removes a color cast so objects that should be neutral white or gray look neutral. Indoor lighting can give an orange tint; shade can look blue. Saturation controls color intensity. At zero saturation, the image is grayscale. Hue changes which colors appear by shifting them around the color wheel. Increasing saturation will not reliably correct an orange cast; it can make the orange stronger.

Grayscale, sepia and other filters create a chosen appearance. Use an effect because it suits the audience and purpose. A dramatic effect may suit an illustration but make an informational photograph harder to interpret.

Sharpen, soften and repair

Sharpening increases contrast along edges, giving the impression of crisper detail. Too much creates bright halos and makes noise stand out. It cannot restore a badly out-of-focus photograph. Blurring softens detail, helping reduce a distracting background or obscure private details.

The clone tool copies pixels from a chosen source area. A healing tool copies a patch and blends it with the surroundings, useful for small dust spots or marks. Choose a nearby area with a matching texture when cloning, or repeated patches may become obvious. Red-eye removal addresses the red pupils produced by camera flash.

Work through a correction

A school-play photo is dark and orange, but the white costumes still contain detail.

1. Keep the original and edit a copy.
2. Correct white balance using an area that should be neutral white or gray.
3. Raise brightness slightly, watching both faces and costumes.
4. Adjust contrast gently so the picture gains definition without losing detail.
5. Apply light sharpening for the intended screen size.
6. Compare before and after at 100% view, then save the edited copy.

Change one setting at a time so you can tell what caused an improvement or a problem. Orange skin, harsh halos or empty white highlights are reasons to reduce the relevant adjustment. Undo that change or lower its strength; adding more effects usually makes the underlying problem harder to judge.

A layered image lets you change one part without rebuilding everything. Combine this with selections and masks to protect the original pixels while you edit.

Select the area to change

A selection marks where an edit applies. Rectangle and ellipse tools suit regular shapes; a lasso follows a freehand boundary. A magic wand selects similar colors, while subject-selection tools try to find the main subject. Check automated results, especially fine edges. Feathering softens a selection edge so a change blends into its surroundings.

A selection does not tell the editor which layer to change. Check both the selected area and the active layer before painting, deleting or adjusting.

Build with stacked layers

Layers work like transparent sheets stacked above one another. Put a photo on one layer, a heading on another and a background below them. Upper opaque content covers lower content. Lowering opacity makes a layer partly see-through.

Text on its own layer stays editable. A solid band behind it can improve contrast. Move the band below the text and above the photo; otherwise it may cover the heading or disappear behind the photo. Combining parts of pictures is called compositing or photomontage.

Hide with a mask

A layer mask controls visibility without deleting the picture beneath it. In most editors, black hides, white reveals and gray partly reveals. If the mask hides too much of a drawing, paint white on that part of the mask to show it again. Erasing the picture itself removes pixels instead.

This is non-destructive editing: preserving pixels so choices can be revised. Keep copies or duplicate layers, use masks and adjustment layers, and save the layered working file. Flattening combines layers; after saving and closing, the separate parts may be impossible to recover from that flattened file.

Make a drawing into a reusable cut-out

1. Scan a student's drawing and keep the original scan.
2. Select the white paper with the magic wand. Check that pale parts of the drawing have not been selected too.
3. Invert the selection to select the drawing, then add a mask that hides the paper.
4. Refine the edges to remove any white halo.
5. Add a background layer underneath and a title layer above for the poster. Save the layered working version.
6. For a cut-out alone, hide the background and title, then export a PNG with transparency enabled.

Transparent pixels allow whatever is behind the cut-out to show through. PNG and WebP preserve partly transparent edges; GIF supports simple fully transparent areas. JPEG has no transparency and fills those areas with a solid color, often white.

Reopen the exported cut-out against a colored background to check the edges. A PNG can still contain a visible background layer, so the file extension alone does not guarantee a transparent result. Keep the layered version for changes and export a separate final copy for use.

A successful export meets the brief in the place it will be used. Plan the output before editing so you know which dimensions, format and quality to preserve.

Follow a complete workflow

List the required audience, message, dimensions, format, file-size limit and house style. Find or create images you are allowed to use, keep the originals and make a working copy. Crop, resize, correct and combine the images, then export a copy. Check every requirement against the export and trial it with someone from the intended audience.

Keep originals, editable working files and final exports organized. Use descriptive names and a version or date. Web filenames work best with simple letters, numbers and hyphens, avoiding spaces and special characters.

Set output for screens

Use pixel dimensions for screens, slides and web pages. Export the size the brief or platform asks for. RGB is the screen color model, and sRGB is the standard web color profile. JPEG or WebP often suits photos; PNG or SVG suits graphics and text, depending on whether they are bitmap or vector.

A full-screen slide image may be specified as 1920 × 1080, while a square post may be 1080 × 1080. These are examples of dimensions, not permanent rules for every service. Check current platform guidance when no size is given.

Calculate output for print

For print, multiply physical inches by the required ppi. At 300 ppi, a US Letter page of 8.5 × 11 inches needs 2550 × 3300 pixels. A3 is 297 × 420 mm, about 11.7 × 16.5 inches, and needs about 3508 × 4961 pixels at 300 ppi using the millimeter dimensions.

Ask the print shop which format and color mode it needs. PDF and CMYK are common requests. Ask about bleed, the image area extending beyond the cut edge so trimming does not leave a white strip. Use a print proof to judge colors instead of relying only on the screen.

Prepare a web banner step by step

The brief requests a science-fair banner, 1200 × 400 pixels, under 300 KB and in school colors. Start with a 4000 × 3000 photo.

1. Find the target ratio: 1200:400 simplifies to 3:1.
2. Keep the 4000-pixel width and crop to about 1333 pixels high. Position the crop around the subject.
3. Resize to the requested 1200 × 400 output, checking the framing and proportions.
4. Add readable title text on its own layer using the house font and colors.
5. Export a JPEG and check its actual dimensions, size and appearance.

If the export exceeds 300 KB, lower JPEG quality slightly and compare again. A smaller file with unreadable title text still fails the brief. For transparent work, check the transparency option and reopen the file against a colored background.

Finally check image credits, readability and alt text for online use. Keep the layered working file so you can fix feedback without repeatedly editing an already compressed JPEG.

Finding a picture is different from having permission to use it. Check rights before spending time editing an image for a slide, poster or public page.

Understand copyright

Copyright gives the creator or other rights holder control over uses such as copying, sharing and adapting an original work. It covers photographs, drawings, text, music, video and software. Protection generally begins automatically when original work is created in a recorded form; a copyright symbol or registration is not needed for that protection to begin.

Treat an online picture as protected until you verify its status. A missing © symbol, easy download or public social post does not make it freely reusable. Copyright often lasts for the creator's life plus 70 years, but the term depends on the country and kind of work. Do not decide a picture is public domain just because it looks old.

Find a valid route to use

There are several routes:

• Create your own image.
• Get permission from the copyright owner and keep the written reply.
• Follow a license that permits the intended use.
• Use a work whose public-domain status you have checked.
• Use an applicable exception in copyright law.

A license is permission with conditions. Check the permitted audience, editing, commercial use and any other restrictions. Royalty-free describes a payment arrangement without a separate royalty for each permitted use; the license can still cost money and restrict what you do.

The public domain contains works not protected by copyright, for example because protection expired, rights were waived where possible or copyright never applied. Status can differ across countries. Museum or library open-access pages can help you verify the status of a specific image.

Separate permission, exceptions and credit

Copyright exceptions allow certain uses without asking permission. Examples include some teaching, criticism and review uses. The United States uses fair use; several other countries use fair dealing. The rules depend on the use and the country. A classroom use and a public upload need separate consideration.

Attribution identifies the creator and source. It is good academic practice and often a license requirement, but it does not supply permission on its own. Writing "Image from Google" names a search service, not the image owner or a valid license. Plagiarism means presenting someone else's work as your own, a separate honesty problem even when copying is permitted.

Suppose a news site has a useful photo with no reuse license. For a public school-fair poster, ask the rights holder or choose an image with verified permission. For a museum image clearly marked public domain, record the museum's source details and credit it as good practice.

Check software and font licenses too

Software licenses can limit devices and permitted uses. Copying or using software without a valid license is software piracy. Product keys, activation, account sign-in, digital rights management and sometimes hardware dongles help enforce licenses. Font licenses may also limit commercial use or embedding in a shared file.

Keep licenses and permission records with the project. Copyright problems can lead to removal, payment demands, legal action and damage to an organization's reputation.

Creative Commons helps you find material whose creators have already granted certain permissions. You still need to match the exact license to what you plan to do.

Read the license elements

Creative Commons (CC) provides six standard licenses. Version 4.0 is the current license suite. Every CC license includes BY, meaning attribution. Other elements add conditions:

Noncommercial means the use is not mainly directed toward commercial advantage or payment. Judge the purpose, not just whether the presentation is sold. A classroom explanation and a presentation promoting a product for sale are different uses.

Compare the six licenses

CC BY allows reuse and adaptation, including commercial use, with credit. CC BY-SA adds ShareAlike. CC BY-NC limits the purpose to noncommercial use. CC BY-NC-SA combines that limit with ShareAlike. CC BY-ND allows sharing under its conditions but no sharing of adaptations. CC BY-NC-ND combines the noncommercial and no-shared-adaptations limits.

CC0 is a public-domain dedication tool, not one of the six licenses. It gives up rights as far as the law permits, with fallback permissions. Credit is good practice even when CC0 does not require it. The Public Domain Mark identifies works already free of known copyright restrictions.

Match permission to the planned output

For a public photomontage, choose images licensed for adaptations. If you use CC BY-SA and share your adapted image, apply the same or a compatible license to that adaptation. Simply placing an unchanged image in a collection does not by itself make every separate item in the collection an adaptation.

For a CC BY-ND photo, keep the image unchanged and place your title beside it, or obtain separate permission for an adaptation. Whether a particular edit counts as an adaptation depends on copyright law. Technical changes such as format conversion are allowed under CC 4.0. Read the terms instead of treating ND as a ban on every file operation.

Search, verify and credit

Use a license filter in an image search, Openverse or Wikimedia Commons. Open the image's own page and confirm the author, license and source; filters can be wrong. Some free-photo sites use their own terms. A reverse image search can help trace an image to its source.

Use TASL for an attribution: Title, Author, Source and License. Link the image page and the license, and state changes. For example: "Autumn Path" by Sam Lee, linked to its photo page, CC BY 4.0 linked to its terms; cropped and brightened. Include the title when supplied.

Put credits beside images or on a credits slide identifying slide numbers. In print, provide readable addresses or a credits page. "Photo: Creative Commons" is incomplete because it omits the creator, source and exact license.

An image can be legally licensed yet still be unfair or unsafe to share. Consider the people shown, the information hidden in the file and what viewers will believe happened.

Ask about taking and sharing

Ask people before taking recognizable photos and before sharing them. Explain where the image will appear: a class display and a public website reach different audiences. Follow school rules, including parent or guardian consent where required for students. The photographer's permission and the subject's consent address different concerns.

Choose respectful images that show people fairly. Avoid embarrassing pictures and stereotypes. Think about how the audience may understand gestures, symbols and colors. An image that seems amusing to one group may be hurtful or misleading to another.

Keep edits honest

Correcting brightness or removing distracting edges can make a photo easier to see. An edit that changes the apparent facts is different. Removing a person from a documentary image, for example, can make viewers believe that person was absent. Do not alter news or documentary images in ways that change what happened.

Label photomontages, heavily edited images and AI-created illustrations. A caption such as "Photomontage" tells viewers they are looking at a constructed image. Heavy body retouching can also promote unrealistic expectations; some countries require labels for such images.

Take responsibility for AI output

An AI image tool can help create or edit a visual, but you remain responsible for its use. Decide what the picture needs to communicate and inspect the result. Check hands, text, details, people and stereotypes. Invented objects or garbled wording can undermine the message even when the image looks polished.

Follow the tool's terms and school rules, make your own choices and edits, and disclose the tool's role. Using AI does not by itself make every generated part your own creative work. Do not make realistic fake images of real people without their consent; these can harm the people shown and can be illegal.

Check information beyond the visible picture

Metadata is information stored with a file. Photo metadata, often called EXIF data, can contain a date, camera details and GPS coordinates. Remove location data before publicly sharing personal photos. Check the export's metadata settings as well as the visible image.

For a school-trip slideshow on a public website, first check the consent records. Leave out students who cannot be shown, or use an approved image treatment that makes them unrecognizable. Avoid embarrassing images, remove location metadata, credit the photographer and add useful alt text.

A public social post is still someone's image, and recognizable people still have privacy interests. Trace the photo's permission and consent instead of assuming that public visibility allows reuse.

Accessible content gives people different ways to understand the same message. A slide that looks clear can still be confusing to someone using a screen reader if its images and structure are not prepared properly.

Describe the image's job

Alternative text, or alt text, is a description attached to an image for assistive technology. Describe what matters to the slide's meaning in one or two useful sentences. Start with the relevant content; screen readers already identify an image, so "Image of" usually adds nothing.

For a photo supporting a recycling proposal, write: "Three color-coded recycling bins in the main hallway, labeled paper, plastic and cans." This gives the useful information. A filename or "Three bins" would tell the listener too little about why the picture is there.

For a chart, give its main finding and provide the detailed data in a table or notes. For example: "Column chart: food waste fell from 40 kg in week 1 to 25 kg in week 4." If a logo opens an organization's website, its description should identify the organization or destination.

An image used only for decoration, such as a border, should be marked decorative so a screen reader skips it. Important wording needs to exist as readable text, not only inside an image. If essential wording is within an image, include it in the alternative.

Give slides a usable structure

Use a unique title in each slide's title placeholder. People can navigate by titles without looking at thumbnails. Three slides all titled "Results" are hard to distinguish; specific titles such as "Results: food waste" identify their jobs. Numbered titles such as "Results (1 of 3)" can also distinguish a series.

Check the reading order, the sequence in which assistive technology reads objects. Visual placement does not guarantee that order; it may reflect when objects were added. Put the title first and arrange the remaining text and images in a meaningful sequence. Built-in layouts provide a useful starting structure, but check the finished slide after edits.

Make lists, tables and links meaningful

Use real bullet-list formatting instead of typing decorative symbols into separate text boxes. Give simple data tables a header row, and avoid merged cells or empty cells used as spacing. Tables used just to position objects can make the reading sequence confusing.

Use descriptive link text such as "Download the club schedule." A screentip can explain more when a pointer rests on the link or object. "Click here" leaves the destination unclear, especially in a list of links.

Use a checker and human judgment

Run the program's accessibility checker and fix the issues it reports. Depending on the program, these can include missing titles, alt text, reading order and contrast. Then check by hand: a tool may detect that a description exists without knowing whether it explains the image well. Read the title, text and descriptions in order without relying on the visual layout.

People may view slides from the back of a room, in bright light or through assistive technology. Readable text, accessible media and thoughtful delivery make the message easier to perceive.

Measure text contrast

Contrast ratio compares the lightness of text and its background. It runs from 1:1 for identical colors to 21:1 for black and white. WCAG level AA sets minimum text ratios:

Use a contrast checker on the actual foreground and background. Gray #767676 on white is about 4.54:1, just above the normal-text threshold. Gray #999999 on white is about 2.85:1, below even the large-text threshold. Yellow on white is about 1.07:1 and very difficult to read. White on pure red is about 4.0:1, enough for large text but not normal text. White on navy #003366 is about 12.6:1.

These thresholds concern contrast, not whether the size works across a room. A slide can pass the ratio check while still using text too small for its viewers.

Provide more than color

Do not make meaning depend on color alone. Red and green chart lines may be difficult to distinguish for someone with red-green color blindness. Add direct labels, different line styles, patterns or words. In a schedule, "Late" and "On time" carry meaning even when the colors cannot be distinguished.

Use plain fonts, left-aligned body text and enough line spacing. Keep wording brief and explain abbreviations. Long capitals, extended italics and justified paragraphs can make reading harder.

Make sound and motion accessible

Provide captions for video speech and a transcript for audio. Check captions for names and technical words. Avoid unexpected autoplay sound. When presenting, describe important visual information aloud so listeners do not need to see every detail to follow the point.

Keep motion simple and avoid flashing more than three times in one second because flashing can trigger seizures. For an unattended show, leave each slide visible long enough to read.

Check a complete slide and delivery

A slide has a title in its placeholder, 24 pt dark gray #595959 body text on white and chart lines labeled directly. Its contrast ratio is about 7.0:1, so the text passes. The photo has useful alt text, and reading order runs from title to explanation to photo. Check the slide in the room as well as in the editor.

Share slides or a PDF in advance when possible. Use the microphone if provided, face viewers so people who lip-read can see you, describe charts and leave time to read. Accessibility includes both the file and the way you present it.