When you upload a profile photo, there is no information about the actual size in pixels x pixels, which is crucial when you use PNG og GIF files for crispness. Earlier, the size seemed to be 320 x 320 pixels.
The format has also changed from square to something like 3:2 (width to height), so the bottom part of your old profile photo/image from before the latest change has been cut off.
It would be nice to have some updated information on how to get it right.