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

function changeImages() {
	if (document.images) {
		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) {
  	shop_def = newImage("image/indexmenu/shopinfo.gif");
		shop_ro = newImage("image/indexmenu/shopinfo_ro.gif");
		system_def = newImage("image/indexmenu/system.gif");
		system_ro = newImage("image/indexmenu/system_ro.gif");
		usedcar_def = newImage("image/indexmenu/usedcar.gif");
		usedcar_ro = newImage("image/indexmenu/usedcar_ro.gif");
		resale_def = newImage("image/indexmenu/resale.gif");
		resale_ro = newImage("image/indexmenu/resale_ro.gif");
		preloadFlag = true;
 }
}