图片base64和PIL互相转换

如题

import json
import requests
import base64 as bs64
from PIL import Image
import io

def extra_to_base64(extra):
    def get_image(url):
        for retry in range(5):
            try:
                response = requests.get(url, timeout=3)
                response.raise_for_status()
                return response.content
            except:
                continue
        return None
    try:  
        obj = json.loads(extra)
        image_list = obj['image_list']
        uri = image_list[0]['u']
        url = "https://your_domain/" + uri
        base64str = bs64.b64encode(get_image(url)).decode('utf-8')
        return base64str
    except Exception as e:
       print('fail to parse {}'.format(extra))
       return ''

def base64_to_image_file(base64_string):
    image_data = bs64.b64decode(base64_string)
    image = Image.open(io.BytesIO(image_data))
    image.save('output_image.png')

if __name__ == '__main__':
    extra = ''''''
    base64_str = extra_to_base64(extra)
    print('base64_str={}'.format(base64_str))
    base64_to_image_file(base64_str)