Comment 1 for bug 1573577

The fix is to replace
"self.image.tostring" with "self.image.tobytes" in /usr/share/qreator/qreator/QRCode.py:76 and
"Image.fromstring" with "Image.frombytes" in /usr/lib/python2.7/dist-packages/qrencode/__init__.py:47

The latter is a bug in python-qrencode, which has already been reported at https://bugs.launchpad.net/ubuntu/+source/python-qrencode/+bug/1587249