Hi Mark,

Whenever I'm using an image I always start out by drawing a Rectangle the approximate size I'll need with it's centre at 0,0,0
I then name this Rectangle "Image ref" & use it to align & position my Background Image in one go.
Because the Image ref is already named, I can then easily hide it & start drawing my model Curves.

So in your case now, maybe Hide all the existing model Curves & create a Rectangle to match your Background Image.
Once it's setup & named, Unhide the other Curves, use Select All & move to their new position.
Hide your model Curves again leaving the Image ref so you can reload the Background Image.

Remember to use the Image Properties & have the Image always associated with that 3DM file.

HTH, Colin