Section 508, 1194.22(a)

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"Provide a text equivalent for every non-text element (e.g., via "alt", "longdesc", or in element content). This includes: images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ASCII art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video."

WCAG 1.0 Checkpoint: 1.1


Text is considered accessible to almost all users since it may be handled by screen readers, non-visual browsers, and Braille readers. It may be displayed visually, magnified, synchronized with a video to create a caption, etc. As you design a document containing non-textual information (images, applets, sounds, multimedia presentations, etc.), supplement that information with textual equivalents wherever possible.

When a text equivalent is presented to the user, it fulfills essentially the same function (to the extent possible) as the original content. For simple content, a text equivalent may only need to describe the function or purpose of content. For complex content (charts, graphs, etc.), the text equivalent may be longer and include descriptive information.

Text equivalents must be provided for logos, photos, submit buttons, applets, bullets in lists, ASCII art, and all of the links within an image map as well as invisible images used to lay out a page.

A good test to determine if a text equivalent is useful is to imagine reading the document aloud over the telephone. What would you say upon encountering this image to make the page comprehensible to the listener?


<img src="./images/photo1.jpg" class="thumbnail" />


<img src="./images/elolivo.jpg" class="thumbnail" alt="El Olivo, by David Smith-Harrison" longdesc="./copy/elolivo.html" />

Warning iconWarning: The longdesc tag does not work in all browsers! As an alternative, a simple hyperlink to the long description can also be supplied in the image caption, for example.


Core Techniques for Web Content Accessibility Guidelines 1.0: