The One With The Free Porn - S4-E17
Other mistake: 10:50pm boarding and departure, but it is broad daylight outside. (00:09:25)
The One With The Free Porn - S4-E17
Other mistake: The new York to London time sequence makes no sense. The friends are all wearing the same clothes throughout most of the episode. Emily flies from London back to New York and Ross flies to London, most trans Atlantic flights are overnight. It's very unrealistic that Ross got to London in the same day, and she flew back so quickly after getting back to London' even though Ross had only just said goodbye to her. The characters' clothes show this is all taking place in the same day.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.