import cv2

img = cv2.imread('D:\PT\pic\pc.jpg', cv2.IMREAD_COLOR)
cv2.imshow('RGB', img)
imggr = cv2.imread(r"D:\PT\pic\pc.jpg", cv2.IMREAD_GRAYSCALE)
cv2.imwrite(r"D:\PT\pic\pcg.jpg", imggr)
cv2.imshow('Grayscale', imggr)

imggr = 255 - imggr
cv2.imwrite(r"D:\PT\pic\pcgin.jpg", imggr)
cv2.imshow('Grayscalein', imggr)

imgr = cv2.imread('D:\PT\pic\pc.jpg', cv2.IMREAD_COLOR)
imgr = imgr[:, :, [0, 2, 1]]
cv2.imwrite('D:\PT\pic\pc.jpg', imgr)
cv2.imshow('Rev', imgr)

cv2.waitKey(0)