swap text with image on mouseover (and restore on mouseout)

swap text with image on mouseover (and restore on mouseout)

I have a bunch of divs with numbers (counting records in my database):

<div class="rowcount">1</div>
<div class="rowcount">2</div>
<div class="rowcount">3</div>

on rollover, I'd like to replace the text (the numbers) with an image (/images/button_go.gif).

what's the best way to do that? I can manage to use the jquery.mouseover function but restoring the text on mouseout is troublesome for me. do I need to pass that as a variable? (I do have the rowcount number as a variable available in PHP.

thanks