.item-img {
    padding-bottom: 56.25%;
    margin-bottom: 10px;
    position: relative;
    display: block;
    overflow: hidden;
    width: 100%;
}

.item-img img{
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    vertical-align: middle;
}