@ahojnnes :+1: for `method`, however, I remain convinced these are very different functions for `'sum'` and `'mean'`. Just to reiterate my prior statements - I expect a transform to respect dtype, and with `'sum'` this can never be guaranteed... in fact, for a properly exposed image in nearly every case it will not! `'mean'` could make sense in `skimage.transform`, though perhaps with another name. I think any use of the word 'sample' in the name or docstring is a bad idea because of confusion with the classical DSP definition of that term.

My opinion is that the two modes/methods should be exposed as separate functions (at least publicly).
 * The `'mean'` variant belongs in `skimage.transform`, named `downscale_local_means` or something else descriptive that doesn't include 'sampling' anywhere.
 * The `'sum'` variant belongs in `skimage.measure`, named `sum_local_blocks` or something else descriptive which, again, does not include 'sampling'.

If these were publicly separate functions, we probably wouldn't even expose `mode`/`method`.