An Oshawa man whose predilection for pictures of people wearing diapers led him to the murky world of online porn trading sites has been sentenced to a year in jail.

With credit for the time he's spent on restrictive bail terms and in custody since his arrest in the fall of 2011, Shawn Chiasson is left with a little over five months to serve. He pleaded guilty in late January to a single count of possession of child pornography.

The ruling Thursday by Superior Court Justice Barry MacDougall brings to an end a unique court proceeding. Although Mr. Chiasson -- a 38-year-old former daycare operator and department store Santa -- admitted to downloading and possessing the porn, he contended he has no sexual interest in children.

Rather, Mr. Chiasson, who has a life-long history of incontinence, said he obtained the illegal images along with legal diaper fetish pictures, downloaded en masse in folders swapped on a peer-to-peer website.

Defence lawyer Alan Risen advanced the argument that Mr. Chiasson was "wilfully blind" to the presence of child porn among the diaper pictures he collected.

In his ruling Justice MacDougall said that while Mr. Chiasson's intentions ameliorated the offence to a degree, he's still guilty of possessing "vile and pernicious material'.

"Mr. Chiasson was operating in a very potentially dangerous area and he knew that," the judge said.

"He was aware of the extreme nature of hardcore child pornography that could be and was included in the downloads."

Mr. Chiasson was busted in September 2011 after attracting the attention of Toronto police monitoring a website known to be a trading venue for child pornography. The undercover cops engaged Mr. Chiasson in chats that led to him sharing his diaper-themed pictures.

Police opined that some of those pictures, depicting diaper-wearing children in provocative poses, constituted child porn. Mr. Chiasson disagreed, and a significant portion of his sentencing hearing was dedicated to arguments on the issue.

Thursday Justice MacDougall ruled that while Mr. Chiasson may claim not to have found the diaper pictures in question pornographic, an objective viewer would.

Some of the images were of "very young children holding their legs apart in an unnatural position," the judge noted.

"I find an erotic image of a child can be considered pornographic," he said.

There was no dispute that other images found on Mr. Chiasson's computer were child pornography. During the sentencing hearing, Mr. Chiasson said he intended to discard the illegal material, but hadn't got around to sorting through the hundreds of images he'd downloaded.

At the time of the police raid on his east Oshawa home, Mr. Chiasson was operating a daycare centre. Court heard an investigation revealed no concerns any children had been harmed.

During his testimony at the sentencing hearing, an emotional Mr. Chiasson recalled a lonely and awkward childhood that was exacerbated by his incontinence. He finally found acceptance among people with issues similar to his online and began trading diaper pictures as a way to "make friends", he told the judge.