Since pip freeze indeed shows scikit-image as installed, I presume that you are launching your script/session using a different environment from the one listed by pip. You should make sure that you are in the same environment. Try python -m pip freeze
and python my_script.py
from the same terminal to make sure that you are comparing the same environment.
RealPython has a decent guide on Python environments here.
That was exactly my problem .. Thank you