You can fix that with some custom CSS…
#headerWrapper {
background: #000 url('http://portals.omg.org/dds2/wp-content/uploads/2014/12/dds-background.png') repeat 0 0 !important
}
footer {
background: #CCC url('http://portals.omg.org/dds2/wp-content/uploads/2014/12/dds-background.png') repeat 0 0 !important
}
Go to Appearance > Design Settings and add that CSS to your Custom CSS box, or add it to your custom stylesheet.