Re: cropping doesn’t work well…
I saw your screenshots in trac. Please tell me if I understand what you’re trying to do.
Based on those screenshots, it appears you are trying to crop an avatar and make it a non-square size. Is that true?
If so, avatars (as used in the WordPress world and many other places) have a square dimension. That is why the extra black bar got added to your crop. The Image processing code for changing your avatar is set to output a square-dimensioned image.