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) {
		home_over = newImage("images/button_home-over.gif");
		about_over = newImage("images/button_about-over.gif");
		services_over = newImage("images/button_services-over.gif");
		maternity_over =  newImage("images/button_maternity-over.gif");
		corporate_over =  newImage("images/button_corporate-over.gif");
		hopi_over =  newImage("images/button_hopi-over.gif");
		ihm_over =  newImage("images/button_ihm-over.gif");
		prices_over =  newImage("images/button_prices-over.gif");
		contact_over = newImage("images/button_contact-over.gif");		
		preloadFlag = true;
	}
}