What is the purpose of ChildWindowImage property?

[punker76]

Originally reported at punker76#101

Setting this property to "Information" for example does nothing. No image is shown on child window.

<simpleChildWindow:ChildWindow x:Class="seedingClient.View.Dialogs.InfoDialog"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:simpleChildWindow="clr-namespace:MahApps.Metro.SimpleChildWindow;assembly=MahApps.Metro.SimpleChildWindow"
             ChildWindowHeight="200"
             ChildWindowWidth="550"
             Background="#354052"
             TitleBarBackground="#354052"
             ChildWindowImage="Information"
             Foreground="White"
             IsOpen="True">

    <Grid>
        // content
    </Grid>
</simpleChildWindow:ChildWindow>

MahApps.Metro v1.6.5
MahApps.Metro.SimpleChildWindow v1.5.0
Wpf application based on .NET framework 4.7.1