He was sentenced by the Magistrate's Court in Harare to five days' imprisonment or a fine of $100.
The court ordered that once he has paid the fine or served the prison sentence that he be deported from Zimbabwe. He is still facing separate charges of possessing pornography, to which he has pleaded innocent. He will appear in court again Friday afternoon on those charges.
The state alleges that Reynolds had images of naked men and women on his iPhone 4S.
U.S. Embassy officials brought him some food in court on Friday morning but declined to speak to the media.
Reynolds, 62, resigned from his congressional seat in 1995 after being convicted of statutory rape.