Addition in a custom theme

You can see a example with https://github.com/Lacro59/playnite-defaultextend-theme.

Differents resources disponible with PluginSettings

The SourceName for the plugin is BackgroundChanger

Plugin settings

CustomOption	Type	Default	Description
EnableBackgroundImage	bool	false	Parameters to display or not the plugin background image.
EnableImageAnimatedBackground	bool	false	Indicates if background image animation is enabled.
EnableCoverImage	bool	false	Parameters to display or not the plugin cover image.
EnableImageAnimatedCover	bool	false	Indicates if cover image animation is enabled.

Plugin data for game selected

CustomOption	Type	Default	Description
HasDataBackground	bool	false	Indicates if the game has background images.
HasDataCover	bool	false	Indicates if the game has cover images

Integration of plugin elements with ContentControl

Visibility

Visibility according to the presence of the plugin

<StackPanel Visibility="{PluginStatus Plugin=<PluginId>, Status=Installed}">
</StackPanel>

Visibility depending the element visibility parameter in plugin settings

If the item is not enabled in the plugin settings, it is collapsed.

Visibility according to the visibility of the element

<StackPanel Visibility="{Binding ElementName=<SourceName>_<ElementName>, Path=Visibility}">
</StackPanel>

Plugin elements

Show background images changer

<StackPanel Tag="{PluginSettings Plugin=BackgroundChanger, Path=HasDataBackground}">
	<StackPanel.Style>
		<Style TargetType="{x:Type StackPanel}">
			<Setter Property="Visibility" Value="Visible" />
			<Style.Triggers>
				<DataTrigger Binding="{Binding ElementName=BackgroundChanger_PluginBackgroundImage, Path=Visibility}" Value="Visible">
					<Setter Property="Visibility" Value="Collapsed" />
				</DataTrigger>
			</Style.Triggers>
		</Style>
	</StackPanel.Style>

	<FadeImage x:Name="PART_ImageBackground" Stretch="Uniform" 
			   HorizontalAlignment="Center" VerticalAlignment="Top">
		<FadeImage.ImageOpacityMask>
			<RadialGradientBrush GradientOrigin="0.5,0" Center="0.5,0" RadiusX="2" RadiusY="0.9">
				<RadialGradientBrush.GradientStops>
					<GradientStop Color="Black" Offset="0.3" />
					<GradientStop Color="Transparent" Offset="1" />
				</RadialGradientBrush.GradientStops>
			</RadialGradientBrush>
		</FadeImage.ImageOpacityMask>
	</FadeImage>
</StackPanel>

<!-- BackgroundChanger plugin background -->
<ContentControl x:Name="BackgroundChanger_PluginBackgroundImage"
		HorizontalAlignment="Center" VerticalAlignment="Top" />

Show cover images changer

<StackPanel DockPanel.Dock="Right" VerticalAlignment="Bottom"
            Tag="{PluginSettings Plugin=BackgroundChanger, Path=HasDataCover}">
    <StackPanel.Style>
        <Style TargetType="{x:Type StackPanel}">
            <Setter Property="Visibility" Value="Visible" />
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=BackgroundChanger_PluginCoverImage, Path=Visibility}" Value="Visible">
                    <Setter Property="Visibility" Value="Collapsed" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </StackPanel.Style>
	
    <Image Name="PART_ImageCover" VerticalAlignment="Bottom"
           Height="{Settings GameDetailsCoverHeight}"
           StretchDirection="Both" Stretch="Uniform"
           RenderOptions.BitmapScalingMode="Fant" />
</StackPanel>

<ContentControl x:Name="BackgroundChanger_PluginCoverImage"
                DockPanel.Dock="Right" VerticalAlignment="Bottom"
                Height="{Settings GameDetailsCoverHeight}" />