These and other types of multimedia can present two distinct problems for people with different disabilities. People who are deaf or hard of hearing can generally see the information presented on webpages. But a deaf person or someone who is hard of hearing may not be able to hear the audio track of a video. On the other hand, persons who are blind or have low vision are frequently unable to see the video images but can hear the audio track.
The words in the tag should be more than a description. They should provide a text equivalent of the image. In other words, the tag should include the same meaningful information that other users obtain by looking at the image. In the example of the mayor’s picture, adding an “alt” tag with the words “Photograph of Mayor Jane Smith” provides a meaningful description.