How to Use Pillow (PIL) Inside Blender Addon? I want to do

from PIL import Image


inside a Blender addon. But it throws this error at me:

ModuleNotFoundError: No module named 'PIL'


Thus I've tried to install Pillow via pip like this:

import subprocess
import ensurepip
ensurepip.bootstrap()
pybin = bpy.app.binary_path_python
subprocess.check_call([pybin, '-m', 'pip', 'install', 'Pillow'])


But this doesn't work, either.

What am I doing wrong? :)
I finally had to copy my PIL package from C:\Program Files\Python37\Lib\site-packages\ and moved it into the Blender Foundation\Blender\2.8.2\python\lib\site-packages and everything started working fine.