function changeImage(img_name, actual_image) {
        document[img_name].src = actual_image;
}

function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		tr_04_over = newImage("Portals/27/Skins/07/img/tr_04-over.jpg");
		tr_05_over = newImage("Portals/27/Skins/07/img/tr_05-over.jpg");
		tr_06_over = newImage("Portals/27/Skins/07/img/tr_06-over.jpg");
		tr_07_over = newImage("Portals/27/Skins/07/img/tr_07-over.jpg");
		tr_08_over = newImage("Portals/27/Skins/07/img/tr_08-over.jpg");
		tr_09_over = newImage("Portals/27/Skins/07/img/tr_09-over.jpg");
		preloadFlag = true;
	}
}