You can also use

decibel.places — Mon, 23 Mar 2009 17:08:47 +0000

You can also use onmouseover/onmouseoff in the tag to change the image or background image source - still using Javascript but you don't need to place code anywhere but the element.

<img src="plainimg.jpg" onmouseover="this.src='overimg.jpg'" onmmouseoff="this.src='plainimg.jpg'" />

Yes, there is no need to use

Megan — Mon, 23 Mar 2009 13:58:28 +0000

Yes, there is no need to use javascript for a simple image swap now. All you need is the css :hover pseudo-class. Put your images in as backgrounds, and change them with :hover.

Or did you want to remotely change an image on a different part of a page? I might have seen a CSS example of that somewhere ...