image-redundant-alt
Image alt text must not duplicate adjacent visible text
Checks that an <img> alt text is not identical to other visible text already present in its immediate parent element.
Applies to. Applies to <img> elements with non-empty alt text whose immediate parent element also has other visible text content (i.e. text nodes besides the image itself, commonly an <a> or <button> wrapping both an icon image and a text label). Finding nothing to ask about, it reports notApplicable, not pass: it applies only to what its check flags, and finding nothing there doesn't show that all is well.
Expectation. The image's alt text is not the same (case-insensitive, normalized) as the other visible text already in the same parent. When both are present, assistive technology announces the same words twice for a single control (e.g. an icon-plus-text link where the icon's alt duplicates the link text).
What a finding reports.
alt: the image's alt text, with spacing collapsed. It matches the text next to it.
These data.details fields help to read and reproduce a finding. Apart from reasonCode and the few fields Output schema names as stable, they are not a stable contract: a field may be renamed or dropped in a minor release, so don’t build on them.
Examples
<a href="/"><img alt="Home" src="home.png">Home</a>
The image's alt text ("Home") duplicates the adjacent visible link text word for word — a screen reader announces it twice.
<a href="/"><img alt="Home icon" src="home.png">Home</a>
The alt text ("Home icon") differs from the adjacent text ("Home").
How to check
When this rule can’t decide, it reports cantTell and leaves the question to a person. Each question it can ask is listed here under its reason code, with the steps to answer it. A finding carries the same steps as howToCheck, in the scan’s language. See Output schema.
IMAGE_ALT_REDUNDANT
- Find the image the report names and the text next to it in the same link, button or parent.
- With a screen reader, move to that link or button, or read its computed name in the Accessibility pane, and listen to whether the words are said twice.
- If the image is already hidden from assistive technology, note that nothing is repeated.
Pass. The words are read once: the image is hidden or has alt="", or its alt adds something the text does not say.
Fail. The image's alt repeats the text beside it, so the same words are read twice, a best-practice miss (H2).