Riot - By Svinebræk at en.wikipedia [Public domain], from Wikimedia Commons
Sun - By Eddo (Own work) [Public domain], via Wikimedia Commons
Bodybuilder - By Uploaded by Wikidudeman (Created by Layne Norton) (Layne Norton) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons
Explosion - By U.S. Navy photo by Photographer’s Mate 2nd Class Aaron Peterson. [Public domain], via Wikimedia Commons
Desert - By Tim & Annette (http://www.sxc.hu/photo/63509) [see page for license], via Wikimedia Commons
Wall Street - By Andrés Nieto Porras from Palma de Mallorca, España [CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons
Cancer - By Dr. Cecil Fox (Photographer) [Public domain or Public domain], via Wikimedia Commons
Robot - By BradBeattie at en.wikipedia [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or GFDL (www.gnu.org/copyleft/fdl.html)], from Wikimedia Commons
Group - By Ubba001 (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons