title: Pan & Zoom Image
body: <p>I want to create a simple image viewer in WPF that will enable the user to:</p>
  
  <ul>
  <li>Pan (by mouse dragging the image).</li>
  <li>Zoom (with a slider).</li>
  <li>Show overlays (rectangle selection for example).</li>
  <li>Show original image (with scroll bars if needed).</li>
  </ul>
  
  <p>Can you explain how to do it? </p>
  
  <p>I didn't find a good sample on the web.
  Should I use ViewBox? Or ImageBrush? 
  Do I need ScrollViewer?</p>