Corey Fitzgerald, 39, had previously dated the victim, authorities said.
She had gone to police seeking complaints for harassment and cyber harassment after Fitzgerald posted the photos on a bogus Instagram account, Detective Sgt. James Donatello said.
The victim was completing a statement when she disclosed that he'd also choked her, the sergeant said.
Complaints were sent to Hoboken police, who arrested Fitzgerald at his job at a Washington Avenue gym late last week, he said.
Fitzgerald was sentenced in 2011 to 12 years in state prison in the death of a 4-year-old son of his former live-in girlfriend in Toms River.
He had pleaded guilty to aggravated manslaughter, telling a judge that he'd become angry and pushed the boy down while babysitting in September 2010.
Fitzgerald hid the child's injuries for the next two days before the boy was hospitalized and died, prosecutors said at the time. An autopsy determined that his death had been caused by a blunt abdominal injury, they said.
Fitzgerald also pleaded guilty at the time to what was an unrelated aggravated assault on the boy's mother.
Under the terms of his Aug. 2011 plea deal, Fitzgerald was required to serve a little over 10 years for both crimes before being eligible for parole later this year.
Records show, however, that he was released this past Nov. 4, 2020 after serving nine years.
Fitzgerald remained held Monday at the Bergen County Jail, charged with aggravated assault, harassment and cyber harassment. The New Jersey State Parole Board was notified.
Click here to follow Daily Voice Ridgewood and receive free news updates.