Text alternatives
Images need alternative text
- Rule:
image-alt - Severity: Critical
- WCAG level A
Why it matters
With no alt attribute, a screen reader falls back to the file name: "hero-2024-final-v3.jpg". Whatever the image was communicating is lost.
How to fix it
- Describe what the image conveys in this context, not what it depicts in general.
- Give decorative images alt="" so they are skipped instead of announced.
- When the image is inside a link, the alt text must say where the link goes.
- Do not start with "Image of" — the role is already announced.
In markup
<img src="team.jpg"><img src="team.jpg" alt="The support team in the Berlin office">
<img src="divider.svg" alt="">What the check cannot tell you
The check sees whether alt exists, not whether it is useful. "image1", "photo" and a repeated file name all pass and all fail the reader.
The requirement behind it
This rule is one way of failing the following WCAG 2.2 success criteria. The W3C, which writes the standard, explains each of them:
- 1.1.1 Non-text Content (opens in new tab) — WCAG level A
Further reading
Deque University on image-alt (opens in new tab)
Deque maintains axe-core, the open-source engine our scanner runs. Their page documents the rule as the engine implements it.
Automated checks find failures a browser can prove. They cannot judge whether a caption is accurate, whether an alt text is useful, or whether a page can be operated end to end with a keyboard — those need a person.