The upload of a profile picture for a user always fails, if Kirby runs on Windows OS, e.g. as local development system using XAMPP.
If I want to upload an *.jpg, which is realy a file from my camera, I see:
This is unfortunately not new since Kirby versions, yet tested with Kirby 2.3.0 final.
Hint:
Then I use the Windows Explorer to drop such a picture to the corresponding directory.