body {
    background-color: #000000;
    color: #ffffff;
    font-family: serif;
    font-size: 12pt;
    margin: 0px;
    padding: 0px;
}

div {

}

img.centre {
    margin: 0px;
    margin-top: -150px; /* half the height of the image */
    margin-left: -350px; /* half the width of the image */
    padding: 0px;
    position: absolute;
    top: 50%; /* combined with the negative margins these ensure the image in centred */
    left: 50%;
}