thumbnail as background

hello,
i wanted to change the view of the thumbnails.

Example: http://www.okermassive.de/rcorner

Code (of the example):

<style type="text/css">
<!--

div.transOFF {width: 100px; }
div.transON {width: 100px; opacity:.75;filter: alpha(opacity=75); -moz-opacity: 0.75;}

-->

<div class="transOFF" onmouseover="this.className='transON'" onmouseout="this.className='transOFF'">
<table width="100" height="100" border="0" cellpadding="0" cellspacing="0" onClick="document.location.href = 'blub.html';" style="cursor:pointer; background-image: url(pic.jpg);">
<tr>
<td valign="top"><img src="lo.gif" ></td>
<td align="right" valign="top"><img src="ro.gif" ></td>
</tr>
<tr>
<td valign="bottom"><img src="lu.gif" ></td>
<td align="right" valign="bottom"><img src="ru.gif" ></td>
</tr>
</table></div>

My Problem: To set the thumbnail as the background of the table

with background-image: url({g->image id="%ID%" item=$child image=$child.thumbnail class="%CLASS% giThumbnail"});happens nothing.

I think, i need a g->url !? But what is the correctly code for this?
Or is that wrong, too ?

Can anyone help me?

Fuji

And like always - sorry for my bad english ;)