title: PIL resize image to exact resolution with white color for missing pixels
body: <p>So I have exact (width, height) I want for my image. My image is Transparent.</p>
  
  <p>What I do first is:</p>
  
  <pre><code>image.thumbnail((width, height), Image.ANTIALIAS)
  </code></pre>
  
  <p>But image is still not the exact size I want. Now I want to put this resized image in center and fill it's transparent space and missing space for exact resolution with white pixels. Is it possible to do that ?</p>