display one .gif then mouseover to see another .gif how?

Can anyone tell me how to display one .gif image on a webpage and then display another .gif when someone mouses over or better yet clicks on the first image?

I sure would appreciate help figuring this one out.
Thank,
Michel White
Grape Grower Solutions

 

Thanks is what I meant!

 

<img src="foo.gif" onmouseover="this.src='bar.gif'" onmouseout="this.src='foo.gif'" />

Code (markup):

also, this would be better served in the web development forums.