Boston Marathon bomber Dzhokhar Tsarnaev peered into the security camera in the corner of his jail cell, fussed with his hair while looking in the reflective glass, flashed a two-digit salute like a teenager taking a selfie and then defiantly put up his middle finger.

A photo and video footage of the obscene gesture were released publicly Wednesday, a day after the photo caused a sensation when prosecutors showed it in court to the jury that will decide whether Tsarnaev lives or dies.

The images were taken by a video camera in Tsarnaev's cell three months after the April 2013 marathon bombings killed three people and injured more than 260. It was the day he was taken into court to be formally arraigned on 30 federal charges in the bombing and in the killing of a Massachusetts Institute of Technology police officer.

Prosecutors presented the photo, wedged between vibrant photos of the people Tsarnaev has been convicted of killing, during their opening statement, telling the jury it showed an "unconcerned, unrepentant and unchanged" Tsarnaev.

On Wednesday, Tsarnaev's lawyers tried to blunt the impact of the photo by showing video of Tsarnaev in his cell before and after.

The video shows Tsarnaev pacing around, fixing his hair and then climbing up on a bench and making the gestures. It shows an obvious injury to the side of his face where he was shot during a gunbattle with police days after the bombings.

Defense lawyer Miriam Conrad emphasized Tsarnaev's young age when questioning Assistant U.S. Marshal Gary Oliveira about the video.

"How old was he at that time?" she asked.

Oliveira said he did not know.

"You don't know that he was 19 years old?" Conrad responded.

Testimony in the penalty phase of Tsarnaev's trial was to resume Thursday.