function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

var activeDiv;
var activeImg;
function changeImages() {
	if (document.images && (preloadFlag == true)) {
		// show/hide contentDiv
		if(activeDiv != document.getElementById(changeImages.arguments[2])) {
			activeDiv.style.display = "none";
			activeDiv = document.getElementById(changeImages.arguments[2]);
			activeDiv.style.display = "block";
		}
		else {
			if(changeImages.arguments[1].indexOf("-over") < 0) {
				activeDiv.style.display = "none";
				activeDiv = document.getElementById("intro");
				activeDiv.style.display = "block";
			}
		}
		
		// img rollover
		document[changeImages.arguments[0]].src = changeImages.arguments[1];
	}
}

var preloadFlag = false;
function preloadImages() {
	activeDiv = document.getElementById("intro");
	activeDiv.style.display = "block";
	
	if (document.images) {
		filmstrip_video_camera_over = newImage("images/filmstrip_video-camera-over.jpg");
		filmstrip_graduate_over = newImage("images/filmstrip_graduate-over.jpg");
		filmstrip_dvd_film_over = newImage("images/filmstrip_dvd-film-over.jpg");
		filmstrip_dvds_over = newImage("images/filmstrip_dvds-over.jpg");
		preloadFlag = true;
	}
}