I sometimes go through my pictures collection to find the better ones. e.g. for printing them or compiling an album. I would like this to be easier and have a function to mark favorite pictures, so that I can find them easier. The selection should be more permanent, then the usual selecting pictures. I should be possible to to show only the pictures marked favorite in the album. Ideally this would work outside of Gwenview, e.g. in the file dialogues.