The One With The Dirty Girl - S4-E6
Continuity mistake: When Ross is making out with Cheryl in her apartment, he gets chocolate syrup on his fingers. In the following shots the chocolate syrup has disappeared. While he wipes his hand on the sofa, no way that would leave his hand perfectly clean.
The One With The Dirty Girl - S4-E6
Continuity mistake: At the beginning of the episode where they are watching Ross through the window, Phoebe is leaning forward and standing to the left of the pole next to Chandler. When the shot changes to Ross coming through the door, she is suddenly standing up straight and is now behind Joey and Chandler. (00:00:10)
The One With The Dirty Girl - S4-E6
Continuity mistake: When Ross and Cheryl are standing in the hall outside Cheryl's apartment, she's holding her keys in her right hand when she asks Ross if he'd like to come in, but after Ross makes the joke about Homo erectus, Cheryl opens her hand and the keys have vanished from her hand.
The One With The Dirty Girl - S4-E6
Continuity mistake: Rachel is working on the crossword puzzle and her legs are crossed (first left over right) and they switch back and forth between shots (about four times) without any time to do so.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.