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) {
			nav_home_over = newImage("/images/nav_home-over.gif");
			nav_about_over = newImage("/images/nav_about-over.gif");
			nav_health_over = newImage("/images/nav_health-over.gif");
			nav_media_over = newImage("/images/nav_media-over.gif");
			nav_spanish_over = newImage("/images/nav_spanish-over.gif");
			nav_contact_over = newImage("/images/nav_contact-over.gif");
			preloadFlag = true;
		}
	}