The pictures were posted on an internet forum as part of a discussion about unusual one-night stands.
The user who uploaded the photos, thatcoolguyben, also alleged that Geldof had taken heroin during their fling and claimed that he woke up the next day in a Scientology centre.
The post has since been removed but the Daily Mail reports that Geldof's lawyer has now issued a statement saying that the pictures had been taken for private use.
"The allegations that our client was carrying and injecting heroin are also denied, our client having consumed alcohol with the other individual leading to the 'highs' described and portrayed in the photos," the attorney wrote.
"The evident unreliability of the source emerges from the also fictitious description of their trip to a Scientology centre. Had you undertaken any checking or research before making this posting you would have learned that nobody who is not a member of that organisation is permitted into such buildings."
Geldof is currently thought to be dating Eli Roth.