Setting Button's Content to <Image> via Styles - wpf

Question

Can't get this to work:
<UserControl>
<UserControl.Resources>
<ResourceDictionary>
<Style x:Key="TestStyle" TargetType="{x:Type Button}">
<Setter Property="Button.Content">
<Setter.Value>
<Image Source="D:\Temp\dictionary16.png"/>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
</UserControl.Resources>
<StackPanel VerticalAlignment="Top" HorizontalAlignment="Left">
<Button Style="{StaticResource TestStyle}"/>
<Button Style="{StaticResource TestStyle}"/>
</StackPanel>
</UserControl>
This code throws the following exception (pointing to the second button):
Specified element is already the logical child of another element. Disconnect it first.

Answer 1

The style creates one instance of the Image, you cannot use it in two places like this. You can create the image as a separate resource with x:Shared= false and reference it in the style then a new one will be created in every place the style is used.
e.g.
<UserControl>
<UserControl.Resources>
<Image x:Key="img" x:Shared="false" Source="D:\Temp\dictionary16.png" />
<Style x:Key="TestStyle" TargetType="{x:Type Button}">
<Setter Property="Content" Value="{StaticResource img}" />
</Style>
</UserControl.Resources>
<StackPanel VerticalAlignment="Top" HorizontalAlignment="Left">
<Button Style="{StaticResource TestStyle}" />
<Button Style="{StaticResource TestStyle}" />
</StackPanel>
</UserControl>

Answer 2

Already yesterday i found a user with a similar problem: WPF - Change a button's content in a style?
This post got me to this soloution (couldn't post it because of 8 hour limit of stackoverflow -.-)
<Setter Property="ContentTemplate">
<Setter.Value>
<DataTemplate>
<Image Source="{mcWPF:LangRes imgSettings16, Bitmap}" Height="14"/>
</DataTemplate>
</Setter.Value>
</Setter>
Don't know weather this is more clean/dirty/better than H.B.'s soloution