The Supreme Court has rejected an appeal filed by a graphic designer against a fine imposed for selling computer-generated images of naked girls produced from photographs, in what could be the first ruling to be finalized that treats such images as child pornography.

In a decision dated Monday, the top court's First Petty Bench upheld a lower court decision imposing the fine of 300,000 yen ($2,750) on Akashi Takahashi, 59, for creating and selling images of nude children based on a photo collection.

(The Supreme Court of Japan)

Takahashi had argued the images were "works of art depicting an imaginary character" and would only be illegal if the girls were aged under 18 at the time the images were created.

But the top court rejected his argument as the images had been made from "photographs of actual girls."

The defendant created the images based on a photo collection from the 1980s and sold them online in 2009, according to lower court rulings.

In March 2016, the Tokyo District Court sentenced him to one year in prison, suspended for three years, and imposed a fine of 300,000 yen after finding three of the 34 images created by Takahashi were based on actual girls.

The Tokyo High Court upheld only the 300,000 yen fine in January 2017, saying the photographs used to create the images were old and "it was difficult to assume there was a concrete infringement of the girls' rights."