$(function() {
$(".back img").css("opacity","1.0");

$(".back img").hover(function () {

$(this).stop().animate({
//on rollover the image will be at 10% opacity, you can change this to your linking but I believe 10% looks best
opacity: 0.0
}, "fast");
},

function () {

$(this).stop().animate({
opacity: 1.0
}, "fast");
});
});