if (document.images)
{
  preload_image_object = new Image();
  // set image url
  image_url = new Array();
  image_url[0] = "../images/tab_inactive_left.gif";
  image_url[1] = "../images/tab_inactive_right.gif";
  image_url[2] = "../images/tab_active_left.gif";
  image_url[3] = "../images/tab_active_right.gif";
  image_url[4] = "../images/tab_inactive_left.gif";
  image_url[5] = "../images/dropdown_highlight.gif";
  image_url[6] = "../images/dropdown_bggradient.gif";

   var i = 0;
   for(i=0; i<=3; i++) {
     preload_image_object.src = image_url[i];
   }
     
}