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) {
		var imageArray = new Array(6)
		imageArray[0] = "assets/cabinet.gif";
		imageArray[1] = "assets/concrete_shelter.gif";
		imageArray[2] = "assets/panelized_shelter.gif";
		imageArray[3] = "assets/noncombustible_shelter.gif";
		imageArray[4] = "assets/modified_iso_shelter.gif";
		imageArray[5] = "assets/lightweight_shelter.gif";
		
		lightweight = newImage("assets/lightweight_shelter.gif");
		cabinet = newImage("assets/cabinet.gif");
		concrete = newImage("assets/concrete_shelter.gif");
		panelized = newImage("assets/panelized_shelter.gif");
		modifiediso = newImage("assets/modified_iso_shelter.gif");
		noncombustible = newImage("assets/noncombustible_shelter.gif");
		preloadFlag = true;
		
		var interval = 3000;
		var t = new Array(30);
		//sets up 6x5=30 timeouts, which run for 30xinterval=90 seconds 
		for (var j = 0; j < 5; j+=1) {
			for (var i = 0; i < imageArray.length ; i+=1){
				t[i+j] = setTimeout("changeImages('shelterOver','" + imageArray[i] + "')",interval*(i + 1)+j*interval*imageArray.length);
			}
		}

	}
}