.portfolio-4x4__slide img:hover {
    -moz-transform: scale(1.1);
    -ms-transform: scale(1.1);
    -webkit-transform: scale(1.1);
    -o-transform: scale(1.1);
    transform: scale(1.1);
    filter: gray;
    -webkit-filter: grayscale(100%);
    filter: grayscale(100%);
}