I am attempting to create a WrapPanel with seamless ImageButtons containing Artwork. I put together the following ContentTemplate in the hopes that it would provide the seamless look required; however a thin white-line remained around each of the buttons. Can anyone steer me in the right direction?

<Button.ContentTemplate>
    <DataTemplate DataType="{x:Type local:ArtInfo}">
        <Border Name="border" BorderThickness="0" BorderBrush="blue" Height="280" Width="250" Background="#262c40">
            <StackPanel>
                <Grid>
                    <Grid.Resources>
                        <local:MyConverter x:Key="MyConverter"></local:MyConverter>
                        <ObjectDataProvider x:Key="Properties.Settings" ObjectType="{x:Type lcl:Properties.Settings}" />
                    </Grid.Resources>
                    <Image Name="ArtImage" Margin="10,15,0,0" Height="195" Width="195" VerticalAlignment="Top" >
                        <Image.Source>
                                  <Binding Path="ArtImage"/>
                        </Image.Source>
                    </Image>
               </Grid>
            <TextBlock Text="{Binding Path=ArtClass}" Margin="10,-17,0,0" FontSize="11" Foreground="white" />
            <TextBlock Text="{Binding Path=Student}" Margin="10,0,0,0" FontSize="11" Foreground="white" />
            <TextBlock Text="1998" Margin="10,0,0,0" FontSize="11" Foreground="white" />
        </StackPanel>
    </Border>
    </DataTemplate>
</Button.ContentTemplate>