Reply To: Custom page and post background

[Tom]

Right, so the CSS being generated by those options in your screenshot would be:

body {
    background-image: url( 'URL TO YOUR IMAGE' );
    background-size: 100%;
    background-attachment: fixed;
    background-repeat: repeat;
    background-position: 0% 20 /* finish this line with whatever is behind the dropdown in the screenshot */
}