#555

Request to merge #555 into the master branch.
I just had a thought about this.

In Images, the ordering is ```(x,y)``` whereas in NumPy arrays it is ```[y,x]```.  Does what we are saying here take that into account?  (If the kernel is isotropic then it doesn't matter at all.  But if it's anisotropic then we should make sure that the direction we say things go in the docstring is really the direction they are going in the code.)