function addOverlays( searchClass, tagName) {
	domNode = document;
	var el = new Array();
	var tags = domNode.getElementsByTagName(tagName);
	var tcl = " "+searchClass+" ";
	for(i=0,j=0; i<tags.length; i++) {
		var test = " " + tags[i].className + " ";
		if (test.indexOf(tcl) != -1){
			tags[i].innerHTML="<img src='images/thumb_overlay.png' />";
			tags[i].style.marginTop="-84px";					
		}
}
}