title: Python Turtle - change displayed background image
body: <p>I am writing a Python 3 turtle example program, and am trying to use <code>bgpic()</code> to change the displayed background image.</p>
  
  <p>Here's a simplified version of my program:</p>
  
  <pre><code>import turtle
  import time
  
  screen = turtle.Screen()
  screen.setup(600,400)
  screen.bgpic('image1.gif')
  time.sleep(2)
  screen.bgpic('image2.gif')
  </code></pre>
  
  <p>When I run this program, I'd like to see the initial image, and then see the image change after 2 seconds. Instead, the screen stays blank until <em>after</em> the second image is drawn.</p>
  
  <p>Any help appreciated,
  Thanks!</p>