Need help with Rollover, pop up script

[techgearfree]

I am trying to do this for my website:

http://www.dynamicdrive.com/dynamic...magetooltip.htm

I already have a picture loaded on my site. I want that picture to have the pop up. What do I do to this line:

<a href="#" onmouseover="doTooltip(event,0)" onmouseout="hideTip()"><img src="/images/paypal.gif"></a><br>

so that it doesn't add a new picture that pops up, but makes the original picture on the page have the popup?

Thanks