Images obtained from the public domain:

B-1B image
"B-1 wings swept" by U.S. Air Force photo by Master Sgt. Robert W. Valenca -
        http://www.af.mil/shared/media/photodb/photos/041008-F-1789V-005.jpg.
        Licensed under Public domain via Wikimedia Commons - 
        http://commons.wikimedia.org/wiki/File:B-1_wings_swept.jpg#mediaviewer/File:B-1_wings_swept.jpg