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) {
		index_16_over = newImage("images/index_16_over.gif");
		index_16_down = newImage("images/index_16_down.gif");
		index_18_over = newImage("images/index_18_over.gif");
		index_18_down = newImage("images/index_18_down.gif");
		index_20_over = newImage("images/index_20_over.gif");
		index_20_down = newImage("images/index_20_down.gif");
		index_22_over = newImage("images/index_22_over.gif");
		index_22_down = newImage("images/index_22_down.gif");
		index_24_over = newImage("images/index_24_over.gif");
		index_24_down = newImage("images/index_24_down.gif");
		index_26_over = newImage("images/index_26_over.gif");
		index_26_down = newImage("images/index_26_down.gif");
		preloadFlag = true;
	}
}