Caption accessibility

Captions and alt text are in the same boat: they help users who have trouble viewing images, processing visuals, or use screen readers to access the content. Don't repeat the information that one can get from alt text or an image so that users won't need to hear the same twice.

Complex images that provide a lot of information, like graphs, diagrams, or infographics, have a strong need for captions and extended descriptions that refer to key content and titles.