Looked at new members of this club, almost everyone ~40 years old. So i will pass on this one. :)
Yes, it can be:
1. Winter sale (unlikely, because we all know that there will be one soon).
2. D&D sale. Well, possible, but prior to the winter sale when many people will be waiting for big christmas discounts? Unlikely.
3. New game release. Possible. Oh, and a part of NWN wallpaper can be just as a picture representing dragon, taken from wll known game just not to spoil upcoming game title. So, sometimes picture, is just a picture. :)
P.S. I imagine how GOG team laughs after reading my post. XD