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) {
		IAH_07_IAH_11_over = newImage("images/IAH_07-IAH_11_over.jpg");
		IAH_11_over = newImage("images/IAH_11-over.gif");
		IAH_16_over = newImage("images/IAH_16-over.gif");
		IAH_17_over = newImage("images/IAH_17-over.gif");
		IAH_19_over = newImage("images/IAH_19-over.gif");
		IAH_20_over = newImage("images/IAH_20-over.gif");
		IAH_21_over = newImage("images/IAH_21-over.gif");
		IAH_22_over = newImage("images/IAH_22-over.gif");
		IAH_23_over = newImage("images/IAH_23-over.gif");
		IAH_24_over = newImage("images/IAH_24-over.gif");
		IAH_25_over = newImage("images/IAH_25-over.gif");
		IAH_27_over = newImage("images/IAH_27-over.gif");
            Page_23_over = newImage("images/sub-Page_23-over.gif");
            Page_24_over = newImage("images/sub-Page_24-over.gif");
            
      	preloadFlag = true;
	}
}