title: What's the difference between Camera Roll and Photo Library?
body: <p>UIImagePickerController has these source type constants:</p>
  
  <pre><code>UIImagePickerControllerSourceTypePhotoLibrary
  
  UIImagePickerControllerSourceTypeSavedPhotosAlbum
  </code></pre>
  
  <p>The documentation says one is for the photo library while the other is for the camera roll. </p>
  
  <p>What's the exact difference between these two? Doesn't "Photo Library" contain pictures taken with the camera as well?</p>