.thumb li a:hover {

}

.thumb ul {

}
.thumb li {
	display: inline-block;
	text-align: center;
	line-height: 1.5;
	padding: 0 5px 20px 5px;
}
.thumb li a {
	display: block;
}




a.hover_img{
    background-color:#fff;
    display:block;
    }
a.hover_img img{
    transition:all 0.5s ease;
    }
a:hover.hover_img img{
    opacity: 0.6;
    filter: alpha(opacity=60);
    }