.parent1 {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    overflow: auto;
}

.block1 {
    width: 128px;
    height: 128px;
    position: absolute;
    top: 50%;
    left: 50%;
    margin: -64px 0 0 -64px;}

    .block1 img {
        max-width: 128px;
        height: 128px;
        display: block;
        margin: 0 auto;
        border: none;
    }