var interval = 1500;
  var random_display = 0;
  var imageNum = 0;
  var ImageDir = "";
  imageArray = new Array();

  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 prevImage(place)
  {
    var new_image = getPrevImage();
    document[place].src = new_image;
  } 
  function switchImage(place)
  {
    var new_image = getNextImage();
    document[place].src = new_image;
    var recur_call = "switchImage('"+place+"')";
    timerID = setTimeout(recur_call, interval);
  }