import cv2 import numpy as np img = cv2.imread("image0.jpg", 1) cv2.imshow('src', img) imgInfo = img.shape height = imgInfo[0] width = imgInfo[1] deep = imgInfo[2] newImgInfo = (height*2, width, deep) dst = np.zeros(newImgInfo, np.uint8) # uint8 for i in range(0, height): for j in range(0, width): dst[i, j] = img[i, j] # x y = 2 * h - y - 1 dst[height*2-i-1, j] = img[i, j] for i in range(0, width): dst[height, i] = (0, 0, 255) # BGR cv2.imshow('dst', dst) cv2.waitKey(0)