Checks
Alt text quality
Flags alt text that is a bare filename, a single generic word, or well over 125 characters, since technically-present alt text can still fail to describe the image.
What this check looks for
Among images that already have non-empty alt text, this check flags alt strings under 5 characters, over 125 characters, or matching filename-like patterns — generic words like "image", "photo", or "screenshot" (optionally followed by digits), a bare file extension like .jpg, or patterns like img_1234. Any match warns, listing the offending alt text. If no non-decorative images have alt text at all, it reports "na"; if none of the alt text matches these low-quality patterns, it passes.
Why it matters
An alt attribute that just repeats the filename ("DSC_1042.jpg") or a single generic word ("image") technically satisfies the presence requirement but gives a screen reader user or a search engine no more information than having no alt text at all — it's a missed description, not a real one. Extremely long alt text, on the other hand, usually means someone stuffed keywords in rather than describing the image naturally, which reads as spam to both users and search engines. AI systems weighing whether an image (and the surrounding content) is trustworthy treat generic or filename-style alt text as a weak signal that the page wasn't carefully produced.
How to fix it
Replace filename-style or single-word alt text with a real, specific description:
<!-- Low quality: filename-derived -->
<img src="/img_1042.jpg" alt="img_1042.jpg">
<!-- Low quality: too generic -->
<img src="/headphones-hero.jpg" alt="image">
<!-- Fixed: specific and appropriately concise -->
<img src="/headphones-hero.jpg" alt="Acme wireless headphones in matte black, folded on a wooden desk">Aim for a short phrase (well under 125 characters) that describes what's actually visible, not a keyword list.
See how your site scores on this check