@media (min-width: 575px) {  
body {
    background-image: url("/img/wallpaper-rajud.jpg");
    background-attachment: fixed;
    background-position: center; 
} 
}

@media (max-width: 575px) { 
    body {
        background-image: url("/img/wallpaper-rajud-xs.jpg");
        background-attachment: fixed;
        background-position: center; 
}  
}