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<DataTemplate DataType="{x:Type SomeViewModel}">
    <StackPanel>
        <Image x:Name="SwitchToImage" />

        <i:Interaction.Behaviors>
            <core:DataTriggerBehavior Binding="{Binding StateManager.SwitchToPanelType}" Value="{x:Static dockpanel:Dockables.InternalBrowser}">
                <core:ChangePropertyAction TargetObject="{Binding #SwitchToImage}" PropertyName="Source" Value="avares://YourAssembly/Assets/browser-n.png"/>
            </core:DataTriggerBehavior>
        </i:Interaction.Behaviors>
    </StackPanel>
</DataTemplate>