//alert('included');


function switch_img(img_id, num_start, num_end, direction)
{

	var current_img = document.getElementById(img_id);
	
	
	
	
	if (!window.current_img_num)
	{
	
		window.current_img_num = num_start;
	
	}
	

	var next_img_num = window.current_img_num + 1;
	
	var prev_img_num = window.current_img_num - 1;
	
	
	
	
	
	// overrides for start & end
	
	if (window.current_img_num == num_end)
	{
	
	 next_img_num = num_start;
	
	}
	
	if (window.current_img_num == num_start)
	{
	
	 prev_img_num = num_end;
	
	}
	
	//alert(prev_img_num);
	
	
	
	// switch image
	if (direction == 'next' || direction == null)
	{
	
		// show next image
		current_img.src = current_img.src.replace(window.current_img_num, next_img_num);
		
		window.current_img_num = next_img_num;
	
	}
	else
	{
	
		// show previous image
		current_img.src = current_img.src.replace(window.current_img_num, prev_img_num);
		
		window.current_img_num = prev_img_num;
		
	}

	
}