Using an Image as an Opacity Mask
<UserControl x:Class='SilverlightApplication3.MainPage' xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' xmlns:d='http://schemas.microsoft.com/expression/blend/2008' xmlns:mc='http://schemas.openxmlformats.org/markup-compatibility/2006' mc:Ignorable='d' d:DesignWidth='640' d:DesignHeight='480'> <Canvas> <Image Height="150" Width="200" Source="c:\image.jpg" HorizontalAlignment="Left" Margin="10"> <Image.OpacityMask> <ImageBrush ImageSource="c:\image.png"/> </Image.OpacityMask> </Image> </Canvas> </UserControl>