You can find photo requirements on the following websites:
http://www.travel.state.gov/visa/visaphotoreq/visaphotoreq_5334.html
http://www.travel.state.gov/visa/visaphotoreq/photocomptemplate/photocomptemplate_5330.html
http://www.travel.state.gov/visa/visaphotoreq/photoexamples/photoexamples_5331.html
http://www.travel.state.gov/visa/visaphotoreq/visaphotoreq_5334.html
http://www.travel.state.gov/visa/visaphotoreq/photocomptemplate/photocomptemplate_5330.html
http://www.travel.state.gov/visa/visaphotoreq/photoexamples/photoexamples_5331.html