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) {
		pan_over = newImage("images/pan-over.gif");
		line_over = newImage("images/line-over.gif");
		extraline_over = newImage("images/extraline-over.gif");
		evolution_over = newImage("images/evolution-over.gif");
		wide_over = newImage("images/wide-over.gif");
		extrapan_over = newImage("images/extrapan-over.gif");
		extrapan__over = newImage("images/extrapan%2b-over.gif");
		preloadFlag = true;
	}
}