Despite several threads on this I don't see a solution to my issue. I want to have a layout 1000px wide (so I set the layout width, no problem) and I want the header to be full width so I set the Full width Header option to YES and that's OK except it stretches the header image across the full width. What I want is to have a background color and a centered header image only 1000px wide.

How would I achieve that?

turn off the Full width Header option - add a header image that is 1000px wide to the header image folder (see the onscreen doc to pick the folder) and use the %immage in the 'Configure Header option'
and set the page color in the 'Body Style' option

Thanks for that response. Actually I now realise that the default header image is actually wider than the layout (1300px wide) which made me think it was stretching but in fact it wasn't. So all I had to do was give the class .header-image-container-pre a background color and I was done.