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) {
		weather_over = newImage("images/weather-over.gif");
		atob_over = newImage("images/atob-over.gif");
		ctog_over = newImage("images/ctog-over.gif");
		htok_over = newImage("images/htok-over.gif");
		ltor_over = newImage("images/ltor-over.gif");
		stot_over = newImage("images/stot-over.gif");
		utoz_over = newImage("images/utoz-over.gif");
		preloadFlag = true;
	}
}