Markup Tools for Images

Image Guidelines

Computers and the web are primarily a visual medium.

Images should not rely on colors alone to convey important meaning. This also applies to color selections for text, background, etc.
All images—including and especially image maps—must have text equivalents.
image maps should be usable without images
avoid text-as-images
- tables
- lists
- paragraphs

There are two key accessibility attributes for images:

The "alt" attribute
This provides a string of text briefly describing the contents of an image. It is intended as an alternate text; i.e. a replacement.

This also applies to decorative images with no meaning or content. In these cases, you should specify an empty string for the alt attribute:
<img src="fancy_list_bullet.gif" alt="" />
The "title" attribute
This attribute provides additional information, and is typically displayed as a "tool tip" on graphical browsers.

The title attribute can be applied to most HTML elements to provide more information. It can be used to remove ambiguity for links:
<img src="fancy_list_bullet.gif" alt="" />
It can also be used to provide information about frames in a frameset for users with screen readers.
A note about image maps

When using image maps, you should provide a title for the <map> element, as well as titles and alts for each of the areas that compose the map.