title: How to merge a transparent png image with another image using PIL
body: <p>I have a transparent png image "foo.png"
  and I've opened another image with </p>
  
  <pre><code>im = Image.open("foo2.png");
  </code></pre>
  
  <p>now what i need is to merge foo.png with foo2.png.</p>
  
  <p>( foo.png contains some text and I want to print that text on foo2.png )</p>