over_image3 = newImage('images/over_05.gif');
<!--
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) {
		over_image1 = newImage('images/over_02.gif');
		over_image2 = newImage('images/over_04.gif');
		over_image4 = newImage('images/over_06.gif');
		over_image5 = newImage('images/over_08.gif');
		preloadFlag = true;
	}
}