Alt text for every image: Crawl Audit check 171

Short answer: alt text is the short description a screen reader reads out in place of an image. Search engines use it too. Check 171 fails when any image on the page has no alt attribute at all.

What Crawl Audit checks

• Pass: every <img> has an alt attribute, or there are no images.
• Fail: some don't. The report shows how many out of the total.

An empty alt="" counts as present, which is right for decorative images (check 172). The check can't judge whether your alt text is any good, only that it exists.

What the sources say

• WCAG 1.1.1, level A: "All non-text content that is presented to the user has a text alternative that serves the equivalent purpose", with some exceptions.
• WebAIM's 2026 survey of the top million home pages found missing alt text on 53.1% of them.
• Google: "Google uses alt text along with computer vision algorithms and the contents of the page to understand the subject matter of the image."

Writing good alt text

• Say what the image tells the reader, not what it looks like. W3C: the text alternative "typically isn't a literal description of the image."
• Keep it short: a phrase or a sentence.
• For a linked image, describe where the link goes.
• Skip "image of" or "photo of"; screen readers already say it's an image.

<img src="team-call.jpg" alt="Our developer walking a client through the new checkout">

On devmarde.com

Our homepage had 8 images on 6 October, all with alt text. It passes.

Sources

• W3C, Understanding 1.1.1 Non-text Content and Informative images.
• WebAIM, The WebAIM Million (2026 report, updated 30 March 2026).
• Google Search Central, Image SEO best practices, checked 6 October 2026.