Well, looking at the source code this is how he has the image popup setup:
Code:
<!-- BEGIN NEEDLE VALVE IMAGE POP-UP -->
<h3> Needle Valves</h3>
<div id="forco"><div class="highslidetwo-wrapper">
<a href="images/needle_valves.jpg" class="highslide" onclick="return hs.expand(this, {captionId: 'caption1'})" onkeypress="nextPage();"><img src="images/needle_valves_t.jpg" alt="These pieces should be pretty easy to find for most people at a decent hardware store." title="Click to enlarge" height="150" width="184" /></a></div>
<!-- END NEEDLE VALVE IMAGE POP-UP --> <!-- BEGIN NEEDLE VALVE IMAGE POP-UP -->
<h3> Needle Valves</h3>
<div id="forco"><div class="highslidetwo-wrapper">
<a href="images/needle_valves.jpg" class="highslide" onclick="return hs.expand(this, {captionId: 'caption1'})" onkeypress="nextPage();"><img src="images/needle_valves_t.jpg" alt="These pieces should be pretty easy to find for most people at a decent hardware store." title="Click to enlarge" height="150" width="184" /></a></div>
<!-- END NEEDLE VALVE IMAGE POP-UP -->
with javascript running the show:
http://www.rexgrigg.com/highslide/highslide.js