img_path = r"E:image.jpg"
img = cv2.imread(img_path)
cv2.imwrite(r"E:ret_80.jpg", img, [cv2.IMWRITE_JPEG_QUALITY, 80])
cv2.imwrite(r"E:ret_40.jpg", img, [cv2.IMWRITE_JPEG_QUALITY, 40])
cv2.imwrite(r"E:ret_10.jpg", img, [cv2.IMWRITE_JPEG_QUALITY, 10])
cv2.imwrite(r"E:ret_0.jpg", img, [cv2.IMWRITE_JPEG_QUALITY, 0])