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_gal_over = newImage("images/nav_gal-over.gif");
		nav_comm_over = newImage("images/nav_comm-over.gif");
		nav_ill_over = newImage("images/nav_ill-over.gif");
		nav_book_over = newImage("images/nav_book-over.gif");
		nav_bio_over = newImage("images/nav_bio-over.gif");
		nav_buy_over = newImage("images/nav_buy-over.gif");
		nav_contact_over = newImage("images/nav_contact-over.gif");
		preloadFlag = true;
	}
}