title: PIL's .crop returns image 0x0. So does ImageGrab.grab with specified bbox
body: <p>so I am trying to capture a part of my screen. But it returns me 0x0 image. All my code at the moment is:</p>
  
  <pre><code>from PIL import ImageGrab
  im = ImageGrab.grab(bbox=(466,789,116,439))
  print im
  &gt;&gt;&lt;PIL.Image._ImageCrop image mode=RGB size=0x0 at 0x1E64120&gt;
  </code></pre>
  
  <p>Although without specifying bbox</p>
  
  <pre><code>im = ImageGrab.grab()
  print im
  &gt;&gt;&lt;PIL.Image.Image image mode=RGB size=1280x1024 at 0x1F33198&gt;
  </code></pre>
  
  <p>I also tried to take a fullscreen image and then crop it:</p>
  
  <pre><code>bbox=(466,789,116,439)
  im = ImageGrab.grab()
  print im
  im = im.crop((466,789,116,439))
  print im
  &lt;PIL.Image.Image image mode=RGB size=1280x1024 at 0x1DA41C0&gt;
  &lt;PIL.Image._ImageCrop image mode=RGB size=0x0 at 0x1DA4260&gt;
  </code></pre>
  
  <p>I have literally no idea how it is not working. Haven't found anyone with the same problem, so here I am.
  Thanks in advance</p>
  
  <p>Python 2.7<br>
  PIL 1.1.7</p>