图像格式转换，批量版，自动处理序号。

img_format_conv_multi.py

from PIL import Image
import sys
import os

photo_input_path = r'.'
photo_save_path = r'./new'
photo_list = os.listdir(photo_input_path)
photo_list = [os.path.join(photo_input_path,i) for i in photo_list]
photo_num=len(photo_list)
zfill_n=len(str(photo_num)) + 1

if not os.path.exists(photo_save_path):
	os.mkdir(photo_save_path)

for i in range(photo_num):
    with Image.open(photo_list[i]) as im:
        im.save(photo_save_path + "/" + str(i).zfill(zfill_n) + ".png")