Ok, A little more messing around, it's weird what they are blocking, and what they let through.

Maybe you guys can help me correct my js function.

Works
Code:

---

<script language=javascript>
function ChangeImage(url,width) {
	largeWidth=1000;
	tempUrl = 'http://images.mydomain.com/motors/6500/DSCN' + url + '.jpg';
	document.img0.src=tempUrl+'?w='+width;
}
</script>

---

Doesn't Work
Code:

---

<script language=javascript>
function ChangeImage(url,width) {
	largeWidth=1000;
	tempUrl = 'http://images.mydomain.com/motors/6500/DSCN' + url + '.jpg';
	document.img0.src=tempUrl+'?w='+width;
	document.img0.setAttribute("onClick", "window.open(tempUrl+'?w='+largeWidth,'eBayAuctionPopup','width='+largeWidth+',height=1200')");
}
</script>

---

So, it seems like they are blocking the window.open js command, but I'm not positive.