Stapleton said she took the photo, obtained exclusively by ABC News, on Aug. 9 -- the last day she saw the little girl.
Stapleton said on the day she took the picture of Zahra, the child seemed down and so she thought a picture could cheer her up. Baker initially told her not to take the picture, Stapleton said, because Zahra's eye was bruised. But Stapleton insisted because she wanted to see the little girl smile.
At the time, Stapleton said she didn't think much of the bruise because Zahra's stepmother would often say her daughter was clumsy.
Bobby Green, a former neighbor, told reporters Tuesday that Zahra frequently had bruises but that Elisa Baker would always explain them away. "It's always she fell down, or she rolled out of bed or she didn't have her leg on right and couldn't walk right and fell. It's always Zahra's fault, for her injuries," Green said.
Brittany Bentley, a relative of Zahra's, said Tuesday the girl "was beat almost every time I was over there for just the smallest things" by her stepmother.
"Elisa would get mad, she would take it out on Zahra, things the kid didn't deserve," Bentley said on CBS' "Early Show." "She just had a horrible home life."
Bentley, who is married to Elisa Baker's nephew, said Zahra was locked in her room most of the day and only allowed out for five minutes to eat.
"I just think this was something for a long time that we knew was going to happen, everybody that was close to the family," Bentley said, apparently referring to Zahra's disappearance.