Audit image alt text by checking what each image does in context: describe meaningful information, use alt="" for purely decorative images, and name the action or destination for linked images. Automated checks can locate missing attributes, but a person must judge whether each description is useful and equivalent to the image. For complex charts and diagrams, give a short alt summary and put the full explanation in nearby or linked text.
What good alt text does
Alt text is a text alternative for an image’s information or function. It is not a filename, a caption by default, or a place to list search keywords. The right wording depends on why the image appears and what a reader needs from it on that particular page.
Text alternatives support people using screen readers or speech input, people browsing with images turned off, and image search. The same image can need different alt text in different contexts: a photo used as evidence in an article may need a meaningful description, while the same photo used as a decorative background may need no text alternative.
Classify each image before editing it
For every image, decide whether it is informative, decorative, functional, or complex. These categories reflect purpose, not file type or visual style.
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Informative images
When an image conveys information that matters to the page, describe the information a reader would otherwise miss. Be concise and specific. For example, <img src="dalmatian.jpg" alt="Dalmatian puppy playing fetch"> tells the reader what is happening, rather than merely naming the file or saying “photo.”
Consider the surrounding copy. If it already says exactly what the image communicates, repeating that information in alt text can be redundant. If the image adds a detail, include that detail. Read the alternative alongside the preceding and following text: together, they should convey the relevant meaning without making the reader hear the same information twice.
Decorative or redundant images
If an image adds no information or function—for example, a purely ornamental divider—give it a null text alternative: alt="". This lets assistive technology skip it instead of announcing a filename or irrelevant visual detail. An image can also be redundant when nearby text already conveys its full meaning and it has no separate function.
Rank #2
Do not omit the alt attribute as a way to indicate decoration. An absent attribute and an empty attribute are not the same: the empty value explicitly marks the image as having no text alternative to announce.
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Images that act as links or controls
When an image is the content of a link or button, describe what the control does or where it goes—not the shape or color of the image. For example, an arrow graphic linking to the next page can use alt="Next page". If nearby text already gives the control’s accessible name, avoid adding a second, confusing announcement.
For an image link, assess the link as a whole. A screen-reader user needs to understand the destination or action from the link’s text alternative, not merely hear that it contains an arrow, logo, or icon.
Rank #3
Charts, diagrams, and maps
Complex images contain more information than a short alt attribute can reasonably carry. Give the image a brief summary, then provide the exact values, relationships, or explanation in surrounding page text or on a linked description page. For example, alt text might say “Line chart showing monthly sign-ups rising from January to June”; the article or an accessible data table should provide the actual values and explain the trend.
Do not try to compress every data point or relationship into one long alt value. A short summary helps readers understand what the graphic is about; the longer text makes its detail available to everyone.
A practical website-wide audit
- Build an inventory. Include meaningful images in CMS content, shared templates, raw HTML, SVGs, image maps, and image-like controls. Include pages rendered dynamically and responsive components, not just a sample of static article HTML.
- Review each image in its page context. Record its purpose—informative, decorative, functional, or complex—and what information or action a reader needs from it. The same asset may serve different purposes in different placements.
- Rewrite informative alternatives. State the image’s relevant information in concise language. Remove details already stated nearby, and avoid adding a generic “image of” prefix unless it helps distinguish the content.
- Mark decoration explicitly. Set
alt=""on purely decorative or fully redundant images. Do not put a filename, visual flourish, or keyword in an empty alternative. - Name actions and destinations. For linked images and image controls, write the destination or action, such as “Next page” or “Search,” rather than describing an arrow or magnifying-glass shape.
- Give complex graphics two levels of explanation. Use a brief alt summary, then place the full explanation or data in nearby text or a linked description.
- Run an automated missing-alt check. Use it to find images with no
altattribute across the pages and templates it can reach. Treat its output as a location list, not as a judgment that the text is good. - Manually inspect flagged and complex images. Compare each image with its wording and nearby content. Confirm that the text alternative is appropriate, that empty alt is intentional, and that a complex image’s detail is available in text.
- Read the page without relying on the image. Read the alt text together with the copy before and after it. If the result does not communicate the necessary meaning or function, revise it.
- Check repeated and responsive components. Inspect the image in each relevant placement or layout. Ensure a shared asset does not acquire conflicting alternatives or become incorrectly decorative in one context because the template assumes all instances behave alike.
- Assign ownership and recheck changes. Decide who updates alternatives when editors replace assets or templates change. Include missing-alt checks in ongoing content or regression review so new omissions are easier to catch.
Automated checks and human review do different jobs
A scanner can identify a missing alt attribute. Depending on what it can access, it may also help you locate images across rendered pages. It cannot reliably decide whether a description conveys the image’s important meaning, whether an image is decorative in context, or whether a chart’s detail is explained elsewhere. Those judgments require seeing the image in context.
When assessing an audit tool or process, consider four practical questions:
- Coverage: Does it reach templates and dynamically rendered pages where your images appear?
- Signal quality: Does it distinguish an absent attribute from an intentional empty value, and help you identify the purpose of the image?
- Context for review: Can an editor see the wording with the actual image and its nearby copy?
- Maintainability: Is there a workflow owner, and are repeated components and later content changes checked?
Do not treat a clean scanner report as proof that every description is useful. Conversely, do not treat every empty alt value as an error: for a purely decorative image, it is the intended result. The strongest process uses automated checks to find candidates and human review to decide what the alternative should say.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Alt text, search, and keyword stuffing
Useful alt text can help search engines understand an image, but its first job is to provide an appropriate text alternative in context. Google advises writing useful, information-rich alt text, using keywords appropriately and in the context of the page. It also warns that keyword stuffing creates a poor user experience and may be treated as spam.
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A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Describe the information or function the image contributes. Do not turn the attribute into a list of search phrases, repeat the page title, or insert terms that do not accurately describe the image. There is no need to add keywords simply because an image has an alt attribute.
Common audit problems and fixes
- The checker reports missing alt, but the image is decorative: Add the attribute with an empty value,
alt="", rather than adding an ornamental description. - The alt text only names a file or says “image”: Replace it with the meaningful information or function the image supplies in context.
- A linked icon is announced as “arrow” or “magnifying glass”: Change the alternative to the action or destination, such as “Next page” or “Search.”
- A chart has a long, dense alt value: Shorten it to a summary and move values and detailed interpretation into page text, a data table, or a linked description.
- The description repeats the paragraph next to the image: Remove the duplication or describe the additional information the image conveys. Review the combination, not the attribute alone.
- A repeated component has inconsistent alternatives: Review all placements and responsive variants. Fix the shared template or content workflow as well as individual instances where needed.
- A scanner says the site passed, but descriptions remain vague: Use the scanner only to locate omissions or other checks it actually supports; manually assess relevance, equivalence, and context.
Or skip the browser setup
If you are collecting page screenshots to review how images sit beside their text, ScreenshotNeo can return a screenshot with one GET request. A screenshot can help an editor see page context, but it does not judge whether alt text is correct; keep the manual review above as part of the audit.
cURL example, using ScreenshotNeo API documentation:
curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webpCookie banners, newsletter popups, and chat widgets are removed before the shot; each step can be turned off. Bot checks, blank pages, timeouts, failed loads, and cache hits are not billed, and the response says which outcome occurred. Its MCP server provides take_screenshot, get_page_info, and capture_pdf tools for AI agents. The Free plan includes 1,000 shots per month with no card; paid plans start at $5 for 3,000 shots. Every feature is available on every plan. Learn about ScreenshotNeo or sign up for 1,000 free screenshots a month with no card.
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Should an image’s alt text mention its colors or visual style?
Only when that visual detail is relevant to the information or function the image provides in its page context.
Is an empty alt value the same as a missing alt attribute?
No. alt="" explicitly marks an image as having no text alternative to announce; an omitted attribute does not.
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