$(document).ready(function(){

			
		$('.photo_thumbnail')
			.css('opacity',0)
			.animate({opacity: 0.6, duration:100})
			.mouseover(function(){
				$(this).stop().animate({opacity: 1, duration:0.3})
			})
			.mouseout(function(){
				$(this).stop().animate({opacity: 0.6, duration:0.3})
			})
			

		
});