Alt Text

Definition

The descriptive text attribute on an image that conveys its meaning to screen readers and search engines.

Alt text is the alternative description attached to an image, read aloud by assistive technology and used by search engines to understand visual content. It is primarily an accessibility requirement, ensuring content is usable by people who cannot see the image, and it secondarily supports image search and topical relevance. Good alt text describes the image concisely and in context, without keyword stuffing, and is left empty for purely decorative images so screen readers can skip them.