kdebase4-wallpapers and 1680x1050

I notice that the kdebase4-wallpapers package for openSUSE 11.1 provides multiple versions of each wallpaper for different screen resolutions. E.g


None of the wallpapers have a 1680x1050 version. Now this isn’t really a problem because with a 1680x1050 screen the wallpapers are still usable, KDE 4 presumably picks what it considers to be most suitable alternative from those provided. However it does make me wonder - why?

Why all those other resolutions but no 1680x1050? Anyone know? Is it a KDE 4 oddity or an oddity of the openSUSE packages?