正则表达式：
    image.png
    image.png

    1. import requests
    3. url='https://pic.qiushibaike.com/system/pictures/12450/124503991/medium/LK5TLE3Z522OASKZ.jpg'
    4. img_data=requests.get(url=url).content
    5. with open('./qiutu.jpg','wb') as fp:
    6.     fp.write(img_data)