I installed the the newest version of the SplashScreen plugin (2.1.0). In the release notes is mentioned that now resolution-specific splashscreens are possible. Unfortunately, it is not mentioned, how to do it.
I checked the source code. From there I assumed, I had to add images with name xxx.screen-720p.jpg (and 2 other names, too). Therefore I added the images to the folder res\screens\wp8. But they were not loaded.
In fact, Application.GetResourceStream() returned always null.
Do I miss something?