The alt element provides alternate text for an image. It is equivalent to the alt attribute on the image element; since the alt attribute is deprecated, use the alt element instead. The alt element can be more easily edited or translated than the alt attribute.
See appendix for information about this element in OASIS document type shells.
The markup for alternate text within an image looks like this:
<image href="tip-ing.jpg"> <alt>Here's a Tip!</alt> </image>