How do I make an image stretch to fill in this WPF / XAML application?

Question

When my program displays an image which is smaller than the Image GUI object defined in XAML, it does not get stretched to fit as I would like it to. For example a 256x256 image only occupies the upper left quadrant of my 512x512 Image GUI object. I am puzzled because I have set Stretch="Fill" in the XAML code. What else do I need to be doing? Any help with the code (see below) would be greatly appreciated.

XAML code defining the GUI

  <Window x:Class="MyProgram.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MyProgarm" Height="900" Width="890" Name="mainWindow" Icon="Icon.ico" MouseDown="mouseDown">
        <Grid Name="mainGrid" Background="#FFEBE7F0" Width="800.10">
          <Border Margin="139,32,0,0" Name="border1" Height="512" VerticalAlignment="Top" HorizontalAlignment="Left" Width="512" Background="#F0D4D0D0" />
          <Border Margin="138,602,0,0" Name="border2" Height="256" VerticalAlignment="Top" HorizontalAlignment="Left" Width="256" Background="#F0D4D0D0" />
          <Border Margin="400,602,0,0" Name="border3" Height="256" VerticalAlignment="Top" HorizontalAlignment="Left" Width="256" Background="#F0D4D0D0" />
          <Image Margin="135,32,0,0" Name="imagePanel1" Stretch="Fill" HorizontalAlignment="Left" Width="512" MouseMove="imagePanelAxl_MouseMove" Height="512" VerticalAlignment="Top" Canvas.Left="-135" Canvas.Top="-32">
          </Image>

Code I use to draw the image:

byte[] myColorImage=// 256x256 RGB image loaded from disk

int W=256;
int H=256;  // dimensions of myColorImage
// Use multiple cores
image.Dispatcher.BeginInvoke(
System.Windows.Threading.DispatcherPriority.Normal,
new Action<byte[]>(
      delegate(byte[] myColorImage_IN)
      {
          const int dpi = 96;

          BitmapSource bmpsrc = BitmapSource.Create(W, H, dpi, dpi, PixelFormats.Bgr24, null, myColorImage_IN, W * 3);
          image.Source = bmpsrc;


      }
  ), myColorImage);

Answer 1

Instead of Image use Image Brush that will do the work for you

 <Border.Background>
            <ImageBrush x:Name="image" Stretch="UniformToFill"/>
 </Border.Background>

And in the Code Behind you can Set

   image.ImageSource = bmpsrc; // if you can give the URL of the File Located on the Disk