Here's some helpful tips on making your graphical
content on users who can't see images:
- Always include an alt attribute on your
<img> tag.
- The alt attribute should contain a short
replacement for the graphic, in text. If the image
itself has text, list that in alt.
- If the image is purely decorative and doesn't convey
any additional information, use alt="".
- If there is more information in the graphic than you
can convey in a short alt attribute, such
as the information in a graph or chart, then use
the longdesc attribute to give the URL of
a page which describes the graphic in text.