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 = newImage("images/b-home.gif");
		nav_homeon = newImage("images/b-home-on.gif");
		nav_services = newImage("images/b-services.gif");
		nav_serviceson = newImage("images/b-services-on.gif");
		nav_contact = newImage("images/b-contact.gif");
		nav_contacton = newImage("images/b-contact-on.gif");
	      preloadFlag = true;
	}
}