function preload_img()
{
  var img_list = preload_img.arguments;
  if (document.preloadlist == null)
    document.preloadlist = new Array();
  var top = document.preloadlist.length;
  for (var i=0; i < img_list.length; i++) {
    document.preloadlist[top+i]     = new Image;
    document.preloadlist[top+i].src = img_list[i];
  }
}