Factual error: This mistake is from series 6 onwards, with Ross' new apartment: There is an impossibility with Ross' kitchen, but not all of the time. It depends on the layout of the hallway outside his apartment. If the hallway continues along for a bit before going left or right, then the kitchen should stick out. However, when the hallway is a dead end, the kitchen fits ok.
Continuity mistake: The white dog that Joey gives Chandler sometimes has red lips and sometimes does not.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.