Why is the image not being authorized in the grid panel?

I tried to create a wp7 application using a blend expression. But is there a problem that makes me go crazy!

I created a Panorama Controller , a Panoramic Element and a Grid . In this grid I create an Image .
enter image description here

Why won't my image expand in width?

Here are the screenshots: The
enter image description here
gray image is also rounded in dx, for example, on the sx side.

Here's the config:
enter image description here

Is there a solution to enlarge the image as wide as the maximum grid size?

How can i do this?

This is my piece of code:

<controls:PanoramaItem Foreground="Black" >
  <Grid Margin="1,26,160,46" Width="418">
    [...]
    <Grid Margin="0,190,8,0" VerticalAlignment="Top" Height="207" >
      <Image Source="JobRow.png" Margin="8,34,27,50" Stretch="None" />
    </Grid>
  </Grid>
</controls:PanoramaItem>

Any idea please?

EDIT 1: Stretch, , !
... , !!!

enter image description here

EDIT 2: !

<controls:PanoramaItem Foreground="Black" Width="438" Orientation="Horizontal">
+3
4

, Width="xxx" XAML, , Expression Blend, .

, !

0

Stretch , , , . , , , , , Fill, Uniform UniformToFill.

Edit:
woudl PanoramaItem, Orientation PanoramaItem Horizontal, , .

+1

, XAML, (Page, UserControl ..). ?

 d:DesignWidth="300"

, :

 d:DesignWidth="800"
0

<Image Source="JobRow.png" Stretch="None" />

,

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