function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function swapImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<swapImages.arguments.length; i+=2) {
			document[swapImages.arguments[i]].src = swapImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		nav_about_r = newImage("images/nav_about_r.gif");
		nav_home_r = newImage("images/nav_home_r.gif");
		nav_portfolio_r = newImage("images/nav_portfolio_r.gif");
		nav_contact_r = newImage("images/nav_contact_r.gif");
		preloadFlag = true;
	}
}