title: snapshotViewAfterScreenUpdates creating a blank image
body: <p>I'm trying to create some composite UIImage objects with this code:</p>
  
  <pre><code>someImageView.image = [ImageMaker coolImage];
  </code></pre>
  
  <p>ImageMaker:</p>
  
  <pre><code>- (UIImage*)coolImage {
      UIView *composite = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 400, 400)];
      UIImageView *imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"coolImage"]]; //This is a valid image - can be viewed when debugger stops here
      [composite addSubview:imgView];
  
      UIView *snapshotView = [composite snapshotViewAfterScreenUpdates:YES];
  //at this point snapshotView is just a blank image
      UIImage *img = [self imageFromView:snapshotView];
      return img;
  
  }
  
  - (UIImage *)imageFromView:(UIView *)view
  {
      UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);
      [view drawViewHierarchyInRect:view.bounds afterScreenUpdates:NO];
      UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
      UIGraphicsEndImageContext();
  
      return img;
  }
  </code></pre>
  
  <p>I just get back a blank black image. How can I fix?</p>