You must add /usr/lib/python3/dist-packages to PYTHONPATH

[jepler]

You must add /usr/lib/python3/dist-packages to PYTHONPATH

[leninberg]

I have followed the instructions from another user here and it worked
sudo apt install -y python-tk
sudo apt install -y python-pil
sudo apt install -y python-imaging-tk
sudo apt install -y libjpeg-progs
sudo apt install -y libimage-exiftool-perl
sudo apt install -y python3.8-distutils
git clone https://github.com/jepler/cropgui.git
cd (to the cloned folder)
sudo bash ./install.sh -p /usr -P /usr/bin/python3

and to execute
python3 cropgtk.py

[logological]

IMHO this issue could/should be reopened. The real issue here is that the error message is not appropriate to the problem (i.e., a missing dependency).

[4L3XK]

On Debian 11 installing this little helper package worked fine for me:
$ sudo apt install python-is-python3

(…)
 This is a convenience package which ships a symlink to point
 the /usr/bin/python interpreter at the current default python3. It may
 improve compatibility with other modern systems, whilst breaking some
 obsolete or 3rd-party software.
(…)

Can anyone else reconfirm this as the solution, at least for newer Debian and possibly Ubuntu.