#fade_out {
    position: relative;
    height: 100%;
    width: auto;
    margin: 0 auto;
}

#fade_out img {
    position: absolute;
    -webkit-transition: opacity 1s linear;
    -moz-transition: opacity 1s linear;
    transition: opacity 1s linear;
    top: 50%;
    left: 50%;
    transform: translate(-50%, 20%);
}

#fade_out img.top:hover {
    opacity: 0;
}