function nextStep(){
 	window.addEvent('domready', function (){
		var scroll = new Fx.Scroll('listaFotosScroll', {duration: 1000});
						
		var position = $('listaFotosScroll').getScroll();
						
		var increment = position.x + 130;
		scroll.start(increment, 0);
		
	});	
 }

function prevStep(){
				
	window.addEvent('domready', function (){
		var scroll = new Fx.Scroll('listaFotosScroll', {duration: 1000});
						
		var position = $('listaFotosScroll').getScroll();
						
		var increment = position.x - 130;
		scroll.start(increment, 0);
		
	});	
				
}