First I thought I needed to work with BorderBrushes, ImageSources, etc., but then I found out that a simple Image in a simple Border seems to be enough, as you can see in this answer.

This is the reason I thought that (screenshot of the design):

(The first one comes from the file “All_Colours.png” and the third from “Transparant.png”, I don’t care about the second brown square)

In XAML, it looks as follows:

<Border x:Name="box_Interior_Group_Color">
    <Image Source="/Company.Customer.Client;component/Views/views/All_Colours.png"/>
</Border>

...

<Border x:Name="box_Interior_Transparant">
        <Image Source="/Company.Customer.Client;component/Views/views/Transparant.png" />
</Border>

… but when I run this, this is what I see:

You might think “you need to copy the files “All_Colours.png” and “Transparant.png” to your runtime directory”, but that’s the point:

• I have copied those files to the runtime directory and to the “Modules” directory (I’m working on a DLL, located in a “Modules” subdirectory of the runtime directory), but that didn’t save the issue.
• There is nothing in the output window. I can imagine that Visual Studio wants to show those *.png files and fails, but in that case it must show some information in the output window.

What can I do?