RECENTLY retired Olympic swimmer Michael Phelps’ medals could be in jeopardy after photos of him emerged on Twitter, which may have breached an Olympic regulation.

Phelps appears in two photos, which were leaked on Twitter and were allegedly linked to a fashion campaign for the luxury brand Louis Vuitton.

Rule 40 of the Olympic Games states no athlete can be involved in non-Olympic marketing campaigns from July 18 to August 15, 2012.

If the leaked photographs were found to be approved by Phelps and were leaked intentionally by the brand, he could be stripped of his medals.

However, if the photos were leaked by an unknown person, Phelps will not be penalised, The Daily Mail reports.

The photos were taken by famous photographer Annie Leibovitz, and are understood to be unofficial images that were stolen.

Management for the swimmer also deny approving the photographs that hit the internet on August 13, and say his medals are safe.

Agent Peter Carlisle told The Associated Press there was no issue with the IOC because Phelps had not authorised use of the pictures, which had been leaked by a source that was not known.

“He didn’t violate Rule 40, it’s as simple as that,” Carlisle said in a telephone interview.

“All that matters is whether the athlete permitted that use. That’s all he can control. In this case, Michael did not authorise that use. The images hadn’t even been reviewed, much less approved. It’s as simple as that. An athlete can’t control unauthorized uses any more than you can guarantee someone isn’t going to break into your house.”