function slideShow(cls)
{
	var imgs = $$('.' + cls + ' img');
	var visible = imgs.findAll(function(img){ return img.visible(); });
	
	if(visible.length > 1)
		visible.last().fade({ duration: .3 });
	else
		imgs.last().appear({
			duration: .3, 
			afterFinish: function(){
				imgs.slice(0,imgs.length-1).invoke('show');
			}
		});
}