Two things:

I thought that the `SBInterpolatedImage` (or more specifically the `MultipleImageHelper`) didn't re-centroid using unweighted moments (or necessarily need to calculate the centroid at all) if it was initialized with only one input `Image`.  I'm kind of banking on this fact for the `InterpolatedImage` implementation of the `ImageCorrFunc`, for which any recentroiding would be a very bad thing.  So I think this is a somewhat misleading statement.  There seems to be some centroid calculation stuff inside the `calculateKMax()` etc. functions, which I guess would fail in such cases if these were called.

Also, this behaviour at the C++ layer (centroid wandering out of the image boundaries) should be catchable without a segfault.