body {
    background-image: url('background_image.png');
    
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-size: 100% auto;
    /*icon: url('../logo-metris.ico');*/
    overflow: hidden;
    animation: fadein 4s; /* Some Browsers may not work */
}
@keyframes fadein{
    0%{
        background-image: url('BackgroundFadeInImage.png');
    }
    30%{
        background-image: url('background_image.png');
    }
}