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_programs_over = newImage("/files/nav_programs-over.gif");
		nav_philosophy_over = newImage("/files/nav_philosophy-over.gif");
		nav_about_over = newImage("/files/nav_about-over.gif");
		nav_bookshop_over = newImage("/files/nav_bookshop-over.gif");
		nav_speaking_over = newImage("/files/nav_speaking-over.gif");
		nav_newsletter_over = newImage("/files/nav_newsletter-over.gif");
		preloadFlag = true;
	}
}