When Otis is in jail, Andy laughs at Otis' joke. The scene cuts to a different camera angle and Andy reacts with laughter all over again.
When Mayor Pike introduces Andy and Barney to the FBI agent, he says that Mayberry has the least crime in the whole "country". Later, Mayor Pike tells the woman reporter that Mayberry has the least crime in the whole "state".
Incorrectly regarded as goof above: When Andy calls the photographer by name on the street before having met him, he could have been informed of his name by Barney or Mayor Pike.
When Otis slams the jail cell door, the "brick" wall shakes.
Audience laughter is heard throughout this episode but there is no studio audience observing the filming. It's a laugh track.
When Andy encounters "photographer" Joe Layton and "FBI Agent" Jenkins on the street, he walks up calling both by name. However, Andy couldn't know who Layton is, since he hadn't been introduced to him yet. Only Barney had met Layton, when he came into the courthouse while Barney was talking to Jenkins.
The fact that the photographer was a criminal should have been obvious since the photographer left at the beginning of the ceremony.