批量转换图片位深度

from PIL import Image
import numpy as np
import cv2
import os
# 单张图片
# img = Image.open(r'C:\Users\znjt\Desktop\huhui\40051.jpg')
# img = Image.fromarray(np.uint8(img))
# t = img.convert('L')
# img=Image.fromarray(np.uint8(t)*255)
# img.save(r'C:\Users\znjt\Desktop\huhui\40051(8).jpg')
path
 = r'D:\m_Files\IPI-for-small-target-detection-master\my_images\\'
save_path = r'D:\m_Files\IPI-for-small-target-detection-master\8\\'
for i in os.listdir(path):
    img = Image.open(path+i)
    img = Image.fromarray(np.uint8(img))
    t = img.convert('L')
    img = Image.fromarray(np.uint8(t))  # *255
    img.save(save_path+i)