$(document).ready(function(){

	updateImage();
	$('#previous_box').click(function(){
		previousImage()});
	$('#next_box').click(function(){
		nextImage()});
});


function updateButtons()
{
	if (ImageIndex >1) $('#previous_box').show();
	else $('#previous_box').hide();

	if (ImageIndex < ImageNumTotal) $('#next_box').show();
	else $('#next_box').hide();
}

function updateImage()
{
	var currentImageFileName = FileName + ImageIndex + '.' + FileType; 
	$('#photo').attr('src', currentImageFileName);

	updateButtons();
}

function previousImage()
{
	if (ImageIndex >= 1) {

        ImageIndex--;
        if (ImageIndex == 4) nextImage();
        else updateImage(); 
	}
}

function nextImage()
{
	if (ImageIndex <= ImageNumTotal) {

        ImageIndex++;
        if (ImageIndex == 4) nextImage();
        else updateImage();
	}
}