The Montreal mother accused in the deaths of her three daughters and her husband's first wife told a Kingston, Ont., courtroom Wednesday that photos of one of the girls in revealing clothing was not a dishonour to her.

"[Sahar] was young, it doesn't matter if she took those pictures at that time," Tooba Yahya testified, adding that all teenagers take such images.

Yahya is charged with first-degree murder in the deaths of her daughters Zainab, 19, Sahar, 17, and Geeti Shafia, 13, as well as her co-accused husband Mohammad Shafia's first wife Rona Amir, 52. The couple's eldest son Hamed, 21, is also charged with murder.

The Crown contends the females were victims of so-called honour killings. The accused have pleaded not guilty.

"If they took naked pictures, it wasn't a dishonour," Yahya said earlier Wednesday to a packed courtroom on her third day of testimony.

The Crown grilled Yahya on specific details relating to the discovery of racy photos of her daughters.

She appeared tired and a number of spectators left the courtroom towards the end of the day. At one point, Yahya said she could not remember the date of the funeral for her three daughters.

Photos enraged Shafia

The photos, which depicted her two oldest daughters with their boyfriends and wearing lingerie, have been central to the case. The Crown is trying to nail down exactly when they were discovered by the family.

Yahya has testified she found the pictures several days after the bodies of the four women were discovered in the Kingston Mills lock in June 2009.

However, media interviews show the family holding a nearly identical album in the immediate aftermath of the deaths. Yahya has said they had several identical books.

The photos set the elder Shafia off on an angry tirade — recorded by police — in which he claimed he would cut his daughters with a cleaver if they ever returned to life, and "may the devil shit on their graves."

Yahya testified on Tuesday that Shafia was simply venting his rage, and he had only discovered the photos in mid-July 2009 in a hiding place in the family's Montreal home.

Part of the Crown's case involved testimony from two of the girls' boyfriends in what are alleged to have been forbidden relationships.

The prosecution also questioned Yahya about condoms found in the room belonging to Geeti, Sahar and Amir, which were discovered by their father shortly after their deaths. Why hadn't they sparked the same sort of outrage from him that the pictures had, she was asked.

Yahya testified that Shafia gave them to her but that they "didn't have much value" because they likely belonged to the elder sister Zainab, who was briefly married for 24 hours in May 2009.

Honour killing 'a stupid thing'

Yahya was also queried about an incident in which a boyfriend of Zainab's was discovered in their home but made to leave by brother Hamed.

She said that episode prompted a concern that Zainab might commit suicide, something Yahya said happened in cases of forbidden love in her native Afghanistan.

"You heard about that but you never heard about honour killings in Afghanistan?" prosecutor Gerard Laarhuis asked, referring to a statement made by Yahya on Tuesday.

Mohammad Shafia is escorted into the courthouse in Kingston, Ont., on Dec. 14, 2011. (Lars Hagberg/Canadian Press)

"No, I never heard such a stupid thing," she said.

The Crown also grilled Yahya aggressively on her previous claim that she lied to police about being at the scene of the deaths to prevent her co-accused son Hamed from being tortured.

On July 22, 2009, Yahya told police she was at the lock and heard a splash before fainting and then waking up the next morning. She later recanted that version of events.

"How was that story going to save him from being tortured?" prosecutor Laarhuis asked Wednesday.

Yahya replied that she was telling the officer what she thought he wanted to hear.

Earlier in the trial, court heard that on the day of the drownings, the family had been returning to their home following a trip to Niagara Falls, Ont. They had stopped at a motel in Kingston for the night.

The high-profile trial began in October but was adjourned for three weeks over the holidays. It resumed Monday with Yahya in the witness box. The trial is expected to last another two weeks.

The family moved to Montreal in 2007 after fleeing Afghanistan several years earlier.

With files from CBC's Dan Halton and Melinda Dalton