Detailed alternative description not adequate

Rule

Complex images MUST be briefly described using alt text AND MUST have a more complete long description.

Background

People who are blind cannot see images on a page. In order to give people who cannot see an image access to the information conveyed by the image, it must have a text alternative. The text alternative must describe the information or function represented by the image. Screen readers can then use the alternative text to convey that information to the screen reader user.

When a complex image - such as a chart or graph or infographic - cannot be described adequately in an alt attribute of approximately 250 characters or less, a longer description is required for screen reader users to understand all of the information presented visually. The alternative content can be presented within the page or on another, easily accessible, page.

How to Fix

Fix this issue by ensuring that the long description for the image gives a full description of the content presented visually in the image.