I try to display an image in a WPF based VSIX

in the XAML designer, the image appears fine

<Image x:Name="waitImage Source ="pack://application:,,,/wpf/Resources/progress_1.png" />

but programmatically, the API complains it needs the assembly name, so I load it this way

Assembly assembly = Assembly.GetExecutingAssembly();
string assemblyName = assembly.GetName().Name;
ImageAnimationPath = $"pack://application:,,,/{assemblyName};component/wpf/Resources/progress_{imageIndex}.png";
BitmapImage bitmapImage = new BitmapImage(new Uri(ImageAnimationPath));
imageIndex = (imageIndex % 3) + 1;

at runtime I get an error message :

"Cannot locate resource 'wpf/resources/progress_1.png'."

I expect:

• the image to load fine
• and be available at runtime when the VSIX is deployed or during debugging

I tried:

• properties/copy always on the image
• setting the Build action to Resource (the image disappears form the Solution explorer)
• cleaning the solution

Any help appreciated