The re-trial has begun of US soldier Lynndie England, the woman at the centre of the Abu Ghraib prisoner abuse scandal in Iraq.
Eight of Lynndie England's colleagues have been convicted
Her defence lawyer said he would argue that her learning disability made her too compliant to authority figures.
She faces 11 years in jail if convicted on charges of conspiracy, committing an indecent act and maltreating detainees.
Pte England attempted a plea bargain at a court martial trial in May, but it was rejected by the judge.
He said testimony given during the sentencing phase contradicted her own statements to the court.
At the time, Pte England said that the notorious pictures were taken for the amusement of the Abu Ghraib prison guards.
However, Spc Charles Graner - her boyfriend at the time the pictures were taken - told the sentencing hearing that the photographs were meant to be used as a training aid.
Photographs of Pte England laughing and pointing at naked Iraqi prisoners, and holding another naked prisoner by a leash around his neck, caused outrage around the world
In court in Fort Hood in Texas on Wednesday, defence lawyers told the jury of five military officers that they would argue that Pte England was overly influenced by Graner.
"What mattered to her was her relationship to... Graner," military lawyer Capt Jonathan Crisp said in his opening arguments.
Pictures such as this one showing Pte England shocked the world (AP Photo/Courtesy of The New Yorker)
"She thinks: 'I love him, he loves me, he's not going to do something to hurt me'."
Prosecutor Chuck Neill said Pte England was an active participant who enjoyed enacting the scenes portrayed on camera.
"This was simply for the amusement of Pte England and the other soldiers," he said.
Pte England entered pleas of not guilty in a preliminary hearing on Tuesday.
The trial, which is expected to last about a week, will resume on Thursday, when prosecution witnesses are scheduled to testify.
Graner was found guilty on charges of assault, battery, dereliction of duty and the maltreatment of prisoners in January, and sentenced to 10 years in prison.
He is among eight soldiers sentenced on charges related to abuse at the prison.