Are spy camera pictures admissible as evidence in a court of law?

Are spy camera pictures admissible as evidence in a court of law?

These are spy pictures and video taken without permission with watches, keychains, pens or eye glasses cameras without audio? Are they legal to use for surveillance and investigations?
spy camera is 100% legal for use in the United States, and conforms to all applicable laws. Our spy watch does not record audio, which is illegal according to the federal wiretapping law, 18 U.S.C. § 2512