Free images results:

Think pictures, stock photos and images


Hobby Royalty Free Stock Photography
Author: Pilarin
Baboon Stock Photo
Author: Eminavn
Baboons Royalty Free Stock Photo
Author: Eminavn
Thinking Stock Photo
Author: Bandu

Also, here are some commercial RF-licensed images that match your search criteria:  
Think tank Royalty Free Stock Image
Author: Wil8