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) {
		a_to_c_over = newImage("images/a-to-c-over.gif");
		aircharters_over = newImage("images/aircharters-over.gif");
		roadtransfers_over = newImage("images/roadtransfers-over.gif");
		byroad_over = newImage("images/byroad-over.gif");
		privateaircraft_over = newImage("images/privateaircraft-over.gif");
		preloadFlag = true;
	}
}