var photoIndex = 1; 
var path = ''; //ie. '/sites/images/dodgethebullet/'
var ext = 'png'; 
var numberOfPhotos = 0;

function initGallery( p, n, e ) {
	path = p;
	ext = e;
	numberOfPhotos = n;
	var src = path + photoIndex+'.'+ext;
	document.getElementById('photo').src = src;
}
	
function next() {
	if ( (photoIndex +1)<= numberOfPhotos ) {
	photoIndex ++;	
	var src = path + photoIndex+'.'+ext;
	document.getElementById('photo').src = src;
	
	}
}

function previous() {
	if ( (photoIndex -1)>= 1 ) {
	photoIndex--;
	var src = path + photoIndex+'.'+ext;
	document.getElementById('photo').src = src;
	}
}