If a longer description is needed, that description should be provided in the main body of the document or in supplementary documentation instead of alt text. Long descriptions are often needed for ...

Twitter alt text has a 1,000-character limit ... It may also be important to distinguish when an image is depicting a graph or diagram that carries information in a particular way, such as ...

Alternative text (or alt text for short) is a short description of a graphic that helps people with visual impairments fully ...