An "alt" tag is code that is put into a Web site that gives more information about an image on the page. For instance, a picture of a map may have "Florida Map" as its alt tag. This is useful for a number of reasons. If an image doesn't show on the page, the alt tag information tells the viewer what the picture is about. People who are blind have software that reads off the alt tags so they know what the pictures are on the page. Also, some search engines pay attention to alt tags in deciding what the page content includes.