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) {
		navigation01_over = newImage("http://www.yk.psu.edu/images/navigation/images/navigation01over.gif");
		navigation02_over = newImage("http://www.yk.psu.edu/images/navigation/images/navigation02over.gif");
		navigation03_over = newImage("http://www.yk.psu.edu/images/navigation/images/navigation03over.gif");
		navigation04_over = newImage("http://www.yk.psu.edu/images/navigation/images/navigation04over.gif");
		navigation05_over = newImage("http://www.yk.psu.edu/images/navigation/images/navigation05over.gif");
		navigation06_over = newImage("http://www.yk.psu.edu/images/navigation/images/navigation06over.gif");
		preloadFlag = true;
	}
}