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Image alt text auditor
Missing alt text is the easiest accessibility fault to find and the easiest to leave for later, so most sites carry hundreds.
This lists every image on a page with its alt text and sorts them: described, deliberately decorative, missing, or present but useless.
The four verdicts
Described. There is alt text and it says something. Nothing to do.
Empty alt, decorative. alt="" on a spacer, a flourish or a background. Correct, and worth being deliberate about.
No alt attribute. A screen reader falls back to reading the filename, or skips the image entirely. Always worth fixing.
Alt that says nothing. “image”, “DSC_0413.jpg”, “logo”, or two paragraphs of prose. Present, and no more useful than absent.
<img src="/team.jpg" alt=""> <!-- skipped by screen readers -->
<img src="/team.jpg" alt="team.jpg"> <!-- says nothing -->
<img src="/team.jpg" alt="Four people at a bench"> <!-- useful -->The one that is a real bug
An image inside a link with an empty alt, and no other text in the link, leaves the link with no accessible name. A screen reader announces “link” and nothing else. Icon buttons and logo links are where this lives.
The fix is alt text describing where the link goes, not what the picture shows: a logo linking home is alt="Home" rather than the company name.
What this cannot see
Only <img> tags in the HTML as served. CSS background images have no alt text at all, and content inserted by JavaScript after load is invisible here, as it is to a crawler on its first pass.
For a whole site, a crawl records every image on every page with its alt text, which is the only practical way to work through a few thousand of them.
Questions people ask
- How do I find images missing alt text?
- Paste a page address. Every
<img>in the HTML is listed with its alt text and a verdict, so the ones with no alt attribute at all are immediately visible. - Is empty alt text wrong?
- No:
alt=""is the correct way to mark a decorative image, and it tells a screen reader to skip it. It is only wrong on an image that carries meaning, and on an image inside a link, where the empty alt leaves the link with no name at all. - Does alt text help SEO?
- It is how images get into image search, and it gives the page a little more to be about. That is the smaller half. The larger half is that somebody using a screen reader can use your page at all, which is also what the law says in a growing number of places.
- What makes good alt text?
- Describe what the image shows, in the context of the page, in a sentence or less. Skip “image of”; a screen reader already says it is an image. Do not repeat the caption word for word, and do not use it as somewhere to put keywords.
Other free tools here
- robots.txt tester — Read a site’s robots.txt, say whether a URL is allowed for Googlebot, and flag the directives that do nothing.
- XML sitemap validator — Find a site’s sitemap, check it parses, and report the entries search engines will reject.
- Redirect chain checker — Follow a URL hop by hop and show every redirect between the address you typed and the page that answers.
- All the free tools — one page each, no account on any of them.
- Download a whole crawl as SQLite — when one page is not enough and you want the data itself.