Ошибка в коде с библиотекой OpenCV

Пытаюсь обработать картинку в Python. Выдает ошибку. Помогите.

import cv2
import os
img = open('/Users/alex/auto.jpg', "wb")
img = cv2.flip(img, -1) # flip video image vertically

TypeError: Expected Ptr<cv::UMat> for argument 'src'

Вот такая теперь ошибка:

 gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

cv2.error: OpenCV(4.4.0) /private/var/folders/nz/vv4_9tw56nv9k3tkvyszvwg80000gn/T/pip-req-build-9ugsgs06/opencv/modules/imgproc/src/color.simd_helpers.hpp:92: error: (-2:Unspecified error) in function 'cv::impl::(anonymous namespace)::CvtHelper<cv::impl::(anonymous namespace)::Set<3, 4, -1>, cv::impl::(anonymous namespace)::Set<1, -1, -1>, cv::impl::(anonymous namespace)::Set<0, 2, 5>, cv::impl::(anonymous namespace)::SizePolicy::NONE>::CvtHelper(cv::InputArray, cv::OutputArray, int) [VScn = cv::impl::(anonymous namespace)::Set<3, 4, -1>, VDcn = cv::impl::(anonymous namespace)::Set<1, -1, -1>, VDepth = cv::impl::(anonymous namespace)::Set<0, 2, 5>, sizePolicy = cv::impl::(anonymous namespace)::SizePolicy::NONE]'
> Invalid number of channels in input image:
>     'VScn::contains(scn)'
> where
>     'scn' is 1