if (document.images)
{
preload_image_object = new Image();
// set image url
image_url = new Array();
image_url[0] = "http://webwinworld.net/demos/uniaustralia/img/select_box3.gif";
image_url[1] = "http://webwinworld.net/demos/uniaustralia/img/select_box5.jpg";
/*image_url[2] = "http://mydomain.com/image2.gif";
image_url[3] = "http://mydomain.com/image3.gif";*/

var i = 0;
for(i=0; i<2; i++)
preload_image_object.src = image_url[i];
}