title: How to crop part of gif image?
body: <p><em>Hi every one,</em></p>
  
  <p>i wrote some code to crop large image to small one. </p>
  
  <p>Everything is OK but when i tried GIF images i get the following exception </p>
  
  <p>"<strong>A Graphics object cannot be created from an image that has an indexed pixel format.</strong>"</p>
  
  <p>I'm using Graphics class to do this</p>
  
  <pre><code>Graphics gfx = Graphics.FromImage(croppedBitmap)
  </code></pre>
  
  <p>thank you.</p>