The victim's father said the man's actions led to the girl's suicide.
He must also give a DNA sample for the national data base. He doesn't have to undergo sex-offender treatment, but the judge recommended he attend a course on sexual harassment.
The 20-year-old can't be identified under a statutory publication ban.
The judge said he must meet with a probation officer. He should write his apology to the family and give it to the probation officer, who will convey it to the girl's parents.
"This is not a court of retribution. It is a court that seeks to reform and rehabilitate the young person," he said.
The judge said it was the first time he's sentenced someone for taking an image of someone without their consent or knowledge.
The judge said an adult would have known better and foreseen the consequences. "He is not as morally blameworthy as an adult would be," the judge told the court.
Addressing the man, he told him: "The act depicted in that photo that you took is vile, it is degrading, it is dehumanizing."
The victim's name is also protected by a mandatory publication ban, something her parents say has restricted them in telling her tragic story, which made national headlines before the court-ordered ban.
The girl died at age 17 after she was taken off life-support following a suicide attempt in the spring of 2013. Her family says she was bullied for months as a result of the photo.
"This series of events drained her of her very essence," the judge said, causing her to "fall into a deep, dark hole of despair from which she could not extricate herself."
'I fight ... not to turn into a dark empty shell'
The girl's father delivered a victim-impact statement. He said his life has forever been changed, and hers ended.
"Every morning I wake up with the realization she is gone. I will never hear her voice again. She will never call me, spend the day with me, or watch a movie we both looked forward to seeing together," he wrote.
"I won’t see her graduate from university and enter a career she dreamed of since she was a child. [She] was my only child. I will never walk my daughter down the aisle at her wedding. I will never be a grandfather and enjoy the laughter of a grandchild.
"The hole you left in my life is as big as the hole you left in hers."
He said the "click of a camera" destroyed her life, turning her from a promising, intelligent young woman into an empty ghost.
"Her dreams turned to ashes, her laughter turned to anger and cries," the father wrote.
He said if the young man had told her he was sorry, she would have forgiven him. But, he wrote, he "did nothing when it would have mattered."
"I fight everyday not to turn into a dark empty shell. I’m not able to work. Hobbies I had that were important to me are all long forgotten and sit on shelves in the basement. I suffer from depression and anxiety. I often fear being alone," the father told the court.
"My sense of justice has been shattered and replaced with doubt, cynicism, and a lack of faith."