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 Coral The Beautiful Everglades Bullfrog
Orange Fungus Glacial Puerto Rican Iguana
Popping Out The snail brothers and sisters
Whale Passion and Bee Orange on orange

Download the Bing Earth Day Photo Contest Finalists Windows 7 Theme