Background image over gradient

Question

I have an image with a transparent background which I would like to overlay on my window as an image behind all of the controls.

My window background already has a gradient brush, but what I can tell by Googling and experimenting, you cannot have two background brushes.

Here is the XAML which isn't working. What do you suggest? Maybe there is another way of setting the image.

<Window.Background>
    <LinearGradientBrush EndPoint="0.5,1" MappingMode="RelativeToBoundingBox" StartPoint="0.5,0">
        <GradientStop Color="#FFF7F7F7"/>
        <GradientStop Color="White" Offset="1"/>
    </LinearGradientBrush>
    <ImageBrush ImageSource="/Images/Arrow.png">
    </ImageBrush>
</Window.Background>

Answer 1

You may put an Image control into a top-level Grid, below all other controls:

<Grid>
    <Grid.Background>
        <LinearGradientBrush EndPoint="0.5,1" MappingMode="RelativeToBoundingBox" StartPoint="0.5,0">
            <GradientStop Color="#FFF7F7F7"/>
            <GradientStop Color="White" Offset="1"/>
       </LinearGradientBrush>
    </Grid.Background>
    <Image Source="/Images/Arrow.png">
    <Grid>
        ... all other controls go here
    </Grid>
</Grid>