$(function() {
// OPACITY OF BUTTON SET TO 100%
$(".thumbnail").css("opacity","1.0");
 
// ON MOUSE OVER
$(".thumbnail").hover(function () {

// SET OPACITY TO 60%
$(this).stop().animate({
opacity: 0.6
}, "fast");
},
 
// ON MOUSE OUT
function () {

// SET OPACITY BACK TO 100%
$(this).stop().animate({
opacity: 1.0
}, "fast");
});
});