.showpic {
    font-size: 0;
    position: fixed;
    top: 0;
    width: 100%;
    height: 100%;
    left: 0;
    z-index: 999;
    text-align: center;
}
.showpic span {
    height: 100%;
    display: inline-block;
    vertical-align: middle;
}
.showpic img {
    vertical-align: middle;
    z-index: 999;
    max-width: 50%;
    display: inline-block;
}