Show images with stacking

ImaageStackView.xaml

<UserControl x:Class="EroTool.View.UserCtl.ImageStackView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d" d:DesignHeight="300"
        d:DesignWidth="300">
    <UserControl.Resources>
        <!-- You can set a picture which shows during loading images. -->
        <BitmapImage x:Key="LoadingBig" UriSource="../../Resources/loading_big.png" />
    </UserControl.Resources>
    <Grid>
        <Viewbox>
            <Grid Name="Stacker" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
        </Viewbox>
        <Image Source="{StaticResource LoadingBig}" Stretch="None" RenderTransformOrigin="0.5, 0.5" Name="LoadingAnimation">
            <Image.RenderTransform>
                <RotateTransform Angle="0"/>
            </Image.RenderTransform>
            <Image.Triggers>
                <EventTrigger RoutedEvent="Image.Loaded">
                    <BeginStoryboard Name="Rotate">
                        <Storyboard>
                            <DoubleAnimation Storyboard.TargetProperty="RenderTransform.Angle" From="0" To="360"
                                    Duration="0:0:1.5" RepeatBehavior="Forever" />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>
            </Image.Triggers>
        </Image>
    </Grid>
</UserControl>