Use the ALT tag to describe the function of all images and graphics appearing in your site. The more important the information conveyed by a graphic, the more important it is to have ALT text associated with it. The ALT tag provides alternative text descriptive information for graphical elements of a web page. The text should be a brief description of the image's purpose. The ALT tag helps visitors understand what is on the page if they are not viewing the graphic. This could be because they are blind or are using a text-based browser or graphical browser with the image loading feature turned off.

Graphical elements that add no content to a page, like a divider bar or decorative object, still need ALT tags, but they should be empty, like this: ALT="". By using two quotation marks with no content, you can reduce the amount of distracting text when a page is viewed with graphic capabilities turned off or with a text-based browser.

Image maps should include ALT tag text to describe each hotspot. Complex graphs and charts should be accompanied by a detailed text description elsewhere on the page (or on another page) in addition to having an "alt" tag.

To test your site, clear your cache, set your browser to images "off," and browse your site.

Examples:

Text equivalent for nontext elements such as images and graphics.

Good example of image map ALT tags.

Exercise in Describing Images