Alt text (short for "alternative text") is a text-based description of a photograph or other image. Providing alt text is a key component to making your website's content accessible to everyone.

Alt text is read aloud to users with a visual impairment who use screen readers to browse the web. It can also be useful for SEO rankings.

Unless immediately followed by a caption that describes what is happening in an image, every image should include alt text. More details about alt text best practices is available on the WebAIM site.