Make sure native Icon calls are running within STA threads (resolves loading issues).
Make sure bitmaps are created on UI thread to ensure ownership (resolves display/update issues).
Remove obsolete helper routines (GetParentWindow and IconToImageSourceConverter).
Remove use of resx file
Resource files are marked as "Resource" instead
Resources are loaded via resource dictionaries (either from code behind or XAML directly through binding)
Reduce amount of required image conversions
Also fix overlay of 50 percent transparency (is now rendered half transparent correct instead of adding "white fog")
Remove obsolete image as rendering is done directly in code
Also fix rendering of link indicator at correct image position
Also remove setting Icons of all Windows (as default is application icon anyway)