As ABC11 reported in October, Todd Fair, 40, was fired by Johnston County Sheriff Steve Bizzell after an investigation was launched into the alleged incident.
Bizzell called Fair's behavior unbecoming of an officer, but declined to say exactly what was in the photographs.
He said Fair admitted sending photos to the student.
Johnston County District Attorney Susan Doyle was asked by Bizzell to investigate the incident, and her department called in the SBI.
Fair is now charged with one count of taking indecent liberties with a child, and two counts of disseminating obscenities to a minor.
He was released on a $24,900 bond.
Warrants allege the incident occurred on March 1, 2009.
Fair had been with the sheriff's office for 10 years.
With information from Mickey Lamm/WTSB Radio