nav {
 position: sticky;
 top: 0;
 padding: 5px;
}

img {
    position: static;
}

article {
    position: absolute;
    top: 100px;
    right: 500;
    left: 1000px;
    background-color: antiquewhite;
}

footer {
    position: relative;
}

a.nav {
    position: sticky;
    top: 0;
}

#footer {
    position: fixed;
    bottom: 0;
    right: 0;
}