var images = new Array();
var length = 10;

for(i=1; i<=length; i++){
	images.push((i<10)?"0" + i : i);
}

var directory = "images/pictures/";
var ext = ".gif";
var src = "";
var currImg = Math.floor(Math.random() * images.length);

function firstImg(){
	src = directory + images[currImg] + ext;
	var string = "<img src=\"" + src + "\" id=\"img_picture\" />";
	document.getElementById("picture").innerHTML = string;
}

function nextImg(){
	var img = document.getElementById("img_picture");
	if(!img) {
		firstImg();
	} else{
	
		currImg++;
		if(currImg >= images.length){
			currImg = 0;
		}
		src = directory + images[currImg] + ext;
		img.src = src;
	}
}

function prevImg(){
	var img = document.getElementById("img_picture");
	if(!img) {
		firstImg();
	} else{
	
		currImg--;
		if(currImg < 0){
			currImg = images.length - 1;
		}
		
		src = directory + images[currImg] + ext;
		img.src = src;
	}
}

window.onload = firstImg;