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) {
		kart_01_trondheim_over = newImage("images/kart_01-trondheim_over.jpg");
		kart_01_vest_over = newImage("images/kart_01-vest_over.jpg");
		kart_01_nord_over = newImage("images/kart_01-nord_over.jpg");
		kart_01_oest_over = newImage("images/kart_01-oest_over.jpg");
		kart_01_soer_over = newImage("images/kart_01-soer_over.jpg");
		preloadFlag = true;
	}
}