title: If set myBitmap = null without recycle(), what difference between with recycle()
body: <p>I see the two lines are always together:</p>
  
  <pre><code>myBitmap.recycle();
  myBitmap = null;
  </code></pre>
  
  <p>If I only use:</p>
  
  <pre><code>myBitmap = null;
  </code></pre>
  
  <p>What difference?</p>
  
  <p>Thanks.</p>