Alt text or alternative text is used by screen reader technology to describe information in an image to visually-impaired users. It should be between 100 and 130 characters in length.
How to write alt text for portraits
For all professional portraits of faculty and staff, follow this formula to write alternative text:
Portrait of [First Name] [Last Name]
How to write alt text for other imagery
In writing alternative text for non-portrait images, explain what is going on in the image so that the context is helpful to the user. Thinking of “who, what, when, where, why, and how” is sometimes helpful in drafting. It’s difficult to write all of those in less than 130 characters though, so be sure to focus on what is most important.