Quick answer
The image-alt check passes when every measured <img> element has an alt attribute, including alt="" for intentionally decorative images. It confirms attribute presence, not descriptive quality, accuracy, or whether an image is useful to searchers. A missing attribute is reported by the separate missing-alt rule.
What the issue means
Alt text is a short text alternative for an image:
<img src="trail-shoe.jpg" alt="Red trail running shoe on a rocky path">
Meaningful images need a concise description of their purpose. Decorative images should use an empty alt value so assistive technology can skip them. The alt attribute is different from a filename, caption, tooltip, or hidden keyword list.
Why it matters for SEO
Alt text helps people who cannot see an image understand its role and gives search systems text associated with image content. It does not guarantee image rankings, and adding words unrelated to the image can make the page less useful. Use the text that a reader needs in the surrounding context.
How NOTABIS detects it
The image-alt rule is a page-level passed check created when NOTABIS finds no img:not([alt]) elements in the measured HTML. It does not evaluate the text, distinguish decorative from informative images, inspect CSS background images, or confirm that a lazy-loaded image’s final source has an alternative. An empty alt attribute passes this presence check by design.
How to check it yourself
Inspect every image in the DOM and compare its alt text with the surrounding copy. Ask what information would be lost if the image did not load. Test decorative images with a screen reader or accessibility inspector, and check responsive and client-rendered states.
How to fix it
Add concise, purpose-based alt text to informative images and alt="" to decorative images. Keep product, diagram, and chart descriptions specific without repeating the caption word for word. Use real text for important explanations and do not put a long article in an alt attribute.
<img src="logo.svg" alt="">
<img src="tyre-tread.jpg" alt="Close-up of winter tyre tread pattern">
Recheck the rendered page and accessibility tree after templates or image components change.
When this is intentional or does not need fixing
Decorative separators, background effects, and images whose information is already fully conveyed by adjacent text can use empty alt text. An image that is also a link still needs an accessible name; inspect the anchor separately because empty link text uses a different heuristic.
Related issues
Compare missing image alt text, missing image dimensions, and empty link text. Google’s image SEO guidance explains useful alt text and image context.
Run a NOTABIS audit
NOTABIS confirms which crawled pages have an alt attribute on every measured image and lets you inspect the images that still need a quality review.