Just pushed a version with int types for image type, and tests for them as well.  I tried to hit all of your points, however I realize now that float images are only raised to float types (in the tests) and int images are only raised to int types.  I didn't test float images raised to ints - do you think that is likely to be a problematic omission?  I'm having a hard time thinking of a scenario where it would fail but the tests I do have would pass, but sometimes I'm just not imaginative enough...