South Australian man who photographed sleeping woman's genitals should be jailed, court hears.

A 23-year-old man who took photos of a young woman’s genitals while she slept has pleaded guilty to indecent filming.

Christopher Kenny from Marleston, South Australia was at a New Years Eve party in January 2013 when the act was committed.

The court heard the woman, who knew Kenny, awoke to the sound of a phone camera before she realised what had happened and began demanding the photos be deleted.

The Advertiser reported his friends had also drawn moustaches on the sleeping girl’s face.

It was also heard that Kenny posted on Facebook: “I hope that bitch gets what’s coming to her” after the crown prosecution decided not to proceed with a rape charge against him in January.

Prosecutor Peter Longson said on Wednesday the incident was the second time Kenny had committed the act against the woman and called for his imprisonment.

Longson said his behaviour was "deviant" and that he had been charged with rape but had the charge dropped after it was found the act did not meet the legislative test for the crime.

A victim impact statement taken from the woman's mother described Kenny as a "predatory coward" and revealed her daughter remained traumatised by the events.

The court heard Kenny could face a maximum penalty of two years jail or a $10,000 fine.

Chief Judge Geoffrey Muecke said the case revealed the cruel and hypocritical nature of social media.

"People think they can take photos of a young woman's genitals and save it away and then post on Facebook that she's a bitch and she will get what's coming to her," he said.

"Instagram, Facebook and Twitter, to call them social media is the antithesis of what they are, they are anti-social media."

Defence lawyer Jane Abbey told the court her client regretted his actions and was deeply embarrassed by his behaviour.

"He fully appreciates that the victim has suffered from the result of his actions. He is sorry," she said.

The sentence for the 23-year-old will be handed down in June.