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

function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		um_over = newImage("images/um-over.gif");
		home_over = newImage("images/home-over.gif");
		history_over = newImage("images/history-over.gif");
		beyond_over = newImage("images/beyond-over.gif");
		lsa_over = newImage("images/lsa-over.gif");
		media_over = newImage("images/media-over.gif");
		aareads_over = newImage("images/aareads-over.gif");
		links_over = newImage("images/links-over.gif");
		preloadFlag = true;
	}
}