A Taupo teenager who downloaded photos of naked pre-teen girls onto his family computer later said he did it "for a laugh".

Thomas Daniel Bickner, 19, was convicted in Taupo District Court today on a representative charge of unlawfully possessing 23 digital photographs knowing they were objectionable under the Films, Videos and Publications Classification Act.

Bickner downloaded the offending images in 2010 when he was 17 years old and showed them to his girlfriend before deleting them 10 days later, the court heard.

Several months later his former girlfriend made a complaint to the police who issued a search warrant and forensically recovered copies of the deleted images on the family computer.

Bickner told the police he had downloaded the images "for a laugh", the court heard.

He admitted they were objectionable and would be disgusting to the normal person, he told police.

He confessed it was the biggest mistake he had ever made in his life.

In sentencing Judge Chris McGuire said while the photos were at the lower level on the Court of Appeal scale of objectionable images - in that they showed no sexual activity - the exploitation of young children was inherent in this type of serious offending.

Judge McGuire noted that Bickner had since the offending been sentenced to supervision for car conversion, fraud , burglary and wilful damage.

A psychiatric report indicated Bickner suffered from depression, possible bi-polar ,and Aspergers Syndrome.

He was also a regular cannabis user, the report said.

"Your behaviour bears all the hallmarks of a troubled and bored person," Judge McGuire said.

"You have too much time on your hands, and too little to do."

Bickner was sentenced to 12 months intensive supervision, including psychiatric assessment and counselling, and 200 hours community work.

- © Fairfax NZ News