Every applicant (apart from people residing overseas) does not need to provide a photo with Form N-400. Every photograph is taken during the biometrics appointment at the Application Support Center.
Only applicants who live not in the USA must submit photographs with N-400 Application. These should be 2 recent identical color photos.
The requirements to the photographs are the following: the background must be from white to off-white; it should be printed on thin paper with a glossy finish and never be retouched. The size of every photo is the same as for a passport and is 2×2 inches. Every photo should reflect a full face and frontal view. The measurements of head height should be between 1 to 1 ⅜ inches from top of hair to bottom of chin and eye height is between 1 1/8 to 1 ⅜ inches from photograph bottom. Check for a head to be bare unless it does not contradict the religious beliefs. Use a pencil or felt pen to print the name and A-Number (if any) to the photo back.