title: Rectangle on Image.OpacityMask in Silverlight
body: <p>I want add Rectangle for Image.OpacityMask in WinPhone.</p>
  
  <p>It is very easy on WPF:</p>
  
  <pre><code>&lt;Image 
        Grid.Row="4" Grid.Column="5"
        Height="150"
        Width="200"
        Source="sampleImages/Waterlilies.jpg"&gt;
    &lt;Image.OpacityMask&gt;
      &lt;DrawingBrush&gt;
        &lt;DrawingBrush.Drawing&gt;
          &lt;GeometryDrawing&gt;
            &lt;GeometryDrawing.Geometry&gt;
              &lt;RectangleGeometry Rect="0.05,0.05 0.9,0.9" /&gt;
            &lt;/GeometryDrawing.Geometry&gt;
        &lt;/GeometryDrawing&gt;
        &lt;/DrawingBrush.Drawing&gt;
      &lt;/DrawingBrush&gt;
    &lt;/Image.OpacityMask&gt;
  &lt;/Image&gt;
  </code></pre>
  
  <p>But on WinPhone we can't use DrawingBrush.</p>
  
  <p>How to add Rectangle on OpasityMask for Image on WinPhone?</p>