Keith, I don’t know if this will help, but here’s a screenshot showing the settings I’m using for that page. Don’t be confused by the negative top margin – that’s just so I can extend the image up under the semi-opaque header.
In my case, I’ve done all of this within a single section. If you’re using multiple sections, that might be causing your problem.
If you are using multiple sections and want the image to stay in place as lower sections scroll up, you need to apply the same image (with the same settings) to each of those lower sections.
