Well, thats interesting but it really doesn't work for a lot of games based on those screenshots imo. Maybe it works for some games but for both Mario Galaxy and Skyward Sword as well as the rest really, it makes it look worse cause it looks like a lot of the color just went bye bye
So after taking pics with Fraps, I think it is the Dolphin's native screen capture that makes the screens look odd. Super Mario Galaxy 2 is just as colorful when I take screens with fraps.
vs. your screen