var interval = 3500;
  var random_display = 0;
  var imageDir = "./images/";
  
  var imageNum = 0;
  imageArray = new Array();
  imageArray[imageNum++] = new imageItem (imageDir + "pic2.jpg");
  imageArray[imageNum++] = new imageItem (imageDir + "pic1.jpg");
  imageArray[imageNum++] = new imageItem (imageDir + "pic3.jpg");
  imageArray[imageNum++] = new imageItem (imageDir + "pic4.jpg");
  imageArray[imageNum++] = new imageItem (imageDir + "pic5.jpg");
  imageArray[imageNum++] = new imageItem (imageDir + "pic6.jpg");
  imageArray[imageNum++] = new imageItem (imageDir + "pic7.jpg");
  imageArray[imageNum++] = new imageItem (imageDir + "pic8.jpg");
  
  var totalImages = imageArray.length;
  
  	function imageItem(image_location) {
		this.image_item = new Image();
		this.image_item.src = image_location;
	}
	function get_ImageItemLocation(imageObj) {
		return(imageObj.image_item.src);
	}
	
	function randNum(x, y) {
		var range = y - x + 1;
		return Math.floor(Math.random() * range) + x;
	}
	
	function getNextImage() {
		if (random_display) {
			imageNum = randNum(0, totalImages-1);
		}
		else {
			imageNum = (imageNum+1) % totalImages;
		}
	var new_image = get_ImageItemLocation(imageArray[imageNum]);
	return(new_image);
	}
	
		function getPrevImage() {
		imageNum = (imageNum-1) % totalImages;
		var new_image = get_ImageItemLocation(imageArray[imageNum]);
		return(new_image);
	}
	
	
       function switchImage(place) {
		var new_image = getNextImage();
		document[place].src = new_image;
		var recur_call = "switchImage('"+place+"')";
		timerID = setTimeout(recur_call, interval);
        }