Setting Image Property Stretch to "UniformToFill" doesnt work well on WINRT

I'm using XAML/C#. and I'm trying to set the Image's Stretch property to UniformToFill. it doesn't work as expected. The Images get trimmed, this is my xaml:

<DataTemplate>
     <Grid VariableSizedWrapGrid.ColumnSpan="{Binding ColumnSpan}" Margin="5">
         <Image Stretch="UniformToFill" Source="{Binding ImageHQ}" />
         <StackPanel VerticalAlignment="Bottom" Background="#AA000000">
             <TextBlock Margin="5,5,5,0" FontSize="26" Text="{Binding Name,Mode=OneWay}" FontFamily="Arial Black" />
             <TextBlock Margin="5,0,5,5" FontSize="24" Text="{Binding Section,Mode=OneWay}" Foreground="{Binding SectionColor,Mode=OneWay}" />
         </StackPanel>
     </Grid>
 </DataTemplate>
 

Is there something wrong with my code?

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