$(function() {
		   
// OPACITY OF BUTTON SET TO 50%
$(".hover_img").css("opacity","0.2");

// ON MOUSE OVER
$(".hover_img").hover(function () {
								 
// SET OPACITY TO 100%
$(this).stop().animate({
opacity: 1.0
}, "fast");
},

// ON MOUSE OUT
function () { 

// SET OPACITY BACK TO 50%
$(this).stop().animate({
opacity: 0.2
}, "slow");
});
});