var imageNumber = 4;
	var imageMax = 4;

	function nextImage() {
		imageNumber = imageNumber + 1;
		if (imageNumber > imageMax) {
			imageNumber = 1;
		}
		document.getElementById("bannerImage").src = "img/img" + imageNumber + ".jpg";
	}	

	function prevImage() {
		imageNumber = imageNumber - 1;
		if (imageNumber < 1) {
			imageNumber = imageMax;
		}
		document.getElementById("bannerImage").src = "img/img" + imageNumber + ".jpg";
	}