function change_Img(mainimg,thumbs) {
	var group = document.getElementById(thumbs);
	var links = group.getElementsByTagName('a');
	for (var i=0; i < links.length; i++) {
		links[i].style.backgroundImage = 'url('+links[i].href+')';
		links[i].onclick = function() {
			return false;
		}
    	links[i].onmouseover = function() {
      		return chgImg(this,mainimg);
		}
	}
}
	
function chgImg (image,mainimg) {
  if (!document.getElementById) return true;
  var mainimg = document.getElementById(mainimg);
  mainimg.getElementsByTagName("img")[0].src = image.href;
  return false;
}