Fifty-six-year-old Robert D. Gahlbeck is charged with two counts of kidnapping and two counts of unlawful restraint.
Police say Gahlbeck is related to one of his alleged victims.
Investigators say the girls were clothed in the photos.
Police do not believe the photographs were posted online.
Anyone with additional information about the incident should contact DeKalb police at (815) 748-8400.