$(function() {
// OPACITY OF BUTTON SET TO 100%
$(".photo_img2").css("opacity","1.0");
 
// ON MOUSE OVER
$(".photo_img2").hover(function () {
 
// SET OPACITY TO 50%
$(this).stop().animate({
opacity: 0.5
}, "slow");
},
 
// ON MOUSE OUT
function () {
 
// SET OPACITY BACK TO 100%
$(this).stop().animate({
opacity: 1.0
}, "slow");
});
});