.card{position: relative;
border: none;
}

.card img:hover{opacity: .8; transition:  .5s;}
.card-body{margin:0; padding: 0; text-align: center;}
.card:after{
    content: "\f07a";
    position: absolute;
    left: 5px;
    top: 5px;
    font-family: 'fontAwesome';
    font-size: 25px;
    color: red;
    transition: .5s;
    opacity: .5;
}

.card:hover:after{
    opacity: .9;
    
}