Themeroller shouldn't generate images if user chooses flat background

Themeroller shouldn't generate images if user chooses flat background

When choosing a flat background css should be like:

        background-color: #c0c0c0;

and not:

        background: #c0c0c0 url(images/ui-bg_flat_100_c0c0c0_40x100.png) 50% 50% repeat-x;