Absolute Center (Vertical & Horizontal) an Image

                                          /*CSS background-image Technique*/html {
    width: 100%;
    height: 100%;
    background: url("logo.png") center center no-repeat;
}
 /*CSS + Inline Image Technique*/img {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 500px;
    height: 500px;
    margin-top: -250px;
    /* Half the height */   margin-left: -250px;
    /* Half the width */
}