When should you use Images have a text alternative?

Run this on any page that carries meaning in pictures: product shots, charts, infographics, image links and image buttons. It is the most common accessibility defect on the web and the cheapest to find, so it belongs in every page audit. It is especially worth leaving on for pages assembled by a content management system, where an editor uploading an image is the person who decides whether it gets a description.

It is the wrong instrument for judging whether a description is GOOD. It proves an image has a text alternative and that the alternative is not a file name or a stock word like "photo"; it cannot tell whether "Team photo" does justice to the picture. A page built entirely from CSS background imagery has nothing here to check, because a background image is decoration by definition.

images with no text alternative; alt text that is a file name or URL; placeholder alt text such as "image"

A failure names the image and why: it has no alternative at all, or its alternative is a file name, a URL, or a placeholder word. A screen reader announces such an image as its file name or skips it, so whatever the image said — a price, a product, the label of a button — never reaches the listener. An image link with no alternative is worse: the link itself is announced with no name. Elements the engine could not decide are listed for review and never counted as failures.

There is no threshold to tune. WCAG 1.1.1 is binary: a meaningful image has a text alternative or it does not, and a decorative one is marked as decorative (alt="", role="presentation" or aria-hidden) or it is not. The file-name and placeholder rules come from WCAG's documented failure F30.

SchemaFirst.org publishes community-governed standards for digital QA. ArbiterQA is a supporter and commercial licensee of those standards; citation does not mean SchemaFirst operates ArbiterQA.