if (document.images)
    {
      preload_image_object = new Image();
      // set image url
      image_url = new Array();
      image_url[0] = "../components/cta/emailRo.gif";
      image_url[1] = "../components/cta/offerRo.gif";
      image_url[2] = "../components/cta/phoneRo.gif";
      image_url[3] = "../components/cta/questionRo.gif";

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