mark.py

import ctypes
import urllib2
import time
import sys

if len(sys.argv) > 1: 
  source = sys.argv[1]
else:
  source = "http://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_0304.jpg"
  
while True:
  print("reloading!")
  sun = urllib2.urlopen(source)
  output = open('sun.jpg','wb')
  output.write(sun.read())
  output.close()
  SPI_SETDESKWALLPAPER = 20 
  ctypes.windll.user32.SystemParametersInfoA(SPI_SETDESKWALLPAPER, 0, "sun.jpg" , 0)
  time.sleep(900)