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

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

var bPreloadFlag = false;
function preloadImages() {			
	if (document.images) {		
		icon_home_off = newImage("images/icon_home.gif");		
		icon_home_on = newImage("images/icon_home_on.gif");
		icon_mail_off = newImage("images/icon_mail.gif");
		icon_mail_on = newImage("images/icon_mail_on.gif");
		icon_map_off = newImage("images/icon_map.gif");
		icon_map_on = newImage("images/icon_map_on.gif");
		bPreloadFlag = true;
	}
}