so you'll need to make use of ALT image tags if you want search engines to list a textual description of your images.
Take a look at this:-
<IMG SRC="forum editor.gif">
That's an ordinary tag. Now see the difference when you use the ALT tag:-
<IMG SRC="forum editor.gif" ALT="best forum editor in the world">
Now the search engine has something meaningful to list. Give it a try, and see what happens. Give Google time to take a new look at your site, and then try typing some keywords into a search, using words that you've inserted into your ALT tags.