Earlier this year Bing hosted a contest for user submitted photos relating to Earth Day and this Windows 7 theme from the Windows 7 Personalization Gallery was the result.

Finger Leather CoralThe Beautiful EvergladesBullfrog
Orange FungusGlacialPuerto Rican Iguana
Popping OutThe snailbrothers and sisters
WhalePassion and BeeOrange on orange

Download the Bing Earth Day Photo Contest Finalists Windows 7 Theme