Ok. Coming back to the mask: I sketched roughly what I need. The visible area should be black, the remaining area transparent. File format should be *.png.It will replace the bottom right corner in all movie/music/series etc in grid view, just need to check it works in listviews etc too.
This is actually what I was going to do. The first mask is applied only to the poster image. The new mask is applied to the "grid view area".Is it possible to lay png's oner the top of the grid view giving the same effect until someone can look into the multiple mask issue ?