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_Home_down = newImage("images/Nav_Home-down.gif");
		Nav_BIO_down = newImage("images/Nav_BIO-down.gif");
		Nav_BIO_over = newImage("images/Nav_BIO-over.gif");
		Nav_Websites_down = newImage("images/Nav_Websites-down.gif");
		Nav_Websites_over = newImage("images/Nav_Websites-over.gif");
		Nav_Advertising_down = newImage("images/Nav_Advertising-down.gif");
		Nav_Advertising_over = newImage("images/Nav_Advertising-over.gif");
		Nav_Logos_down = newImage("images/Nav_Logos-down.gif");
		Nav_Logos_over = newImage("images/Nav_Logos-over.gif");
		Nav_GuiDesigns_down = newImage("images/Nav_GuiDesigns-down.gif");
		Nav_GuiDesigns_over = newImage("images/Nav_GuiDesigns-over.gif");
		Nav_Newsletters_down = newImage("images/Nav_Newsletters-down.gif");
		Nav_Newsletters_over = newImage("images/Nav_Newsletters-over.gif");
		Nav_ArtGallary_over = newImage("images/Nav_ArtGallary-over.gif");
		Nav_ArtGallary_down = newImage("images/Nav_ArtGallary-down.gif");
		preloadFlag = true;
	}
}