The sites listed here provide public domain images. Check any individual image to be assured that is in the public domain. Be sure to see the Privacy & Publicity Rights section of this guide.
Image from CDC PHIL (#18172) by National Institute of Allergy and Infectious Diseases (NIAID) is in the public domain
Image from CDC PHIL (#19320) by CDC/CDC Connects (Pamela Cassiday, M.S., Pertussis and Diphtheria Laboratory) is in the public domain
Image from CDC PHIL (#20541) by Cynthia Goldsmith is in the public domain