If you are on Python3 you can also use the library PILasOPENCV which works in Python 2 and 3. Function api calls are the same as in PIL or pillow but internally it works with OpenCV and numpy to load, save and manipulate images. Have a look at https://github.com/bunkahle/PILasOPENCV or install it with pip install PILasOPENCV. Not all PIL functions have been simulated but the most common functions work.