var interval = 1500;
var random_display = 0;
var imageDir = "pictures/";


var imageNum = 0;
imageArray = new Array();
imageArray[imageNum++] = new imageItem(imageDir + "01.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "02.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "03.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "04.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "05.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "06.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "07.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "08.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "09.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "10.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "11.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "12.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "13.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "14.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "15.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "16.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "17.jpg");
imageArray[imageNum++] = new imageItem(imageDir + "18.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 switchImage(place) {
var new_image = getNextImage();
document[place].src = new_image;
var recur_call = "switchImage('"+place+"')";
timerID = setTimeout(recur_call, interval);
}