Use Image as the Grid background
<Window x:Class="OpacityMaskExample" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="" Height="430" Width="300"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions> <Grid Grid.Row="0" Margin="5"> <Grid.Background> <ImageBrush ImageSource="c:\image.jpg" /> </Grid.Background> <Ellipse Width="200" Height="200" StrokeThickness="0" Fill="Yellow" Margin="20"> <Ellipse.OpacityMask> <RadialGradientBrush GradientOrigin="0.5,0.5" Center="0.5,0.5" RadiusX="1" RadiusY="1"> <GradientStop Offset="0" Color="Transparent" /> <GradientStop Offset="1" Color="Yellow" /> </RadialGradientBrush> </Ellipse.OpacityMask> </Ellipse> </Grid> </Grid> </Window>