Provide appropriate descriptions for all informative non-text content
Alternative descriptions are required for all types of images, charts, graphs, and other informative non-text (visual) content. These elements are not as useful for individuals with visual disabilities.
These descriptions, or alt text, are read aloud by assistive technology with text-to-speech functionality.
The alt text should succinctly describe the purpose of the image in the fewest possible words, ideally fewer than 15. If the image is purely for decoration and serves no informative purpose, alternative text is not necessary.
Alternative descriptions can be provided in multiple ways:
- using the built-in function in authoring software
- in the text of the document itself
- as a caption below the content
- using an external resource (e.g., web link, appendix, or other document).