Unfortuanetly? Thats a good thing. I was talking to Can about a TC graphics pack. No more details except on a need-to-know basis =D
Well, it would be unfortunate if you wanted to change the size that the ships appeared at on-screen.
So if I wanted an ocean background, I could make it any size as long as the borders blend? Hypothetically of course.
It doesn't need to tile, if that's what you mean. The game never tiles the background. It does shift it around a tiny bit as you move the view, but that's done by just cropping off margins.