a good file

good.py

# Example

from urllib2 import urlopen
import random

cat = (random.randint(100,500), random.randint(100,500))
site = urlopen('http://placekitten.com/{}/{}'.format(*cat))
data = site.read()

cat_file = open('demoncat.jpg','w')
cat_file.write(data)
cat_file.close()

with open('cat.jpg','wb') as f:
    f.write(data)