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) {
		button1_over = newImage("images/button1_over.jpg");
		button2_over = newImage("images/button2_over.jpg");
		button3_over = newImage("images/button3_over.jpg");
		button4_over = newImage("images/button4_over.jpg");
		button5_over = newImage("images/button5_over.jpg");
		button6_over = newImage("images/button6_over.jpg");
		button7_over = newImage("images/button7_over.jpg");

		preloadFlag = true;
	}
}