Continuity mistake: When Monica and Chandler walk into the apartment with the twins, 2 very bright yellow soothers keep appearing and disappearing from the babies' mouths. (00:18:50)
Continuity mistake: While Mama Joey is looking for Chick Jr. and Duck Jr., the things pinned to the bulletin board beside the door have vanished when Monica and Chandler walk in, but after Monica walks out to check on the twins everything's back up on the board like it was before.
Continuity mistake: In the hospital when Erica is giving birth and the camera is on the doctor, the door to the room is closed. However, when the camera angle changes, the door is wide open even though no one had entered or exited.
Continuity mistake: On the plane, when Rachel says "She's almost never right," (about Phoebe) you can see the guy's hand is on the armrest. Then a split second later, his hand is about half a feet off the armrest while saying "But she is sometimes." (00:15:15)
Continuity mistake: When the friends put down their keys, the keys' positions change when the camera pans the apartment. (00:25:30)
Continuity mistake: When Phoebe's driving Ross to the airport in her cab the rear view mirror vanishes from the windshield, then it reappears and disappears again. Additionally, when they start their drive the cab doesn't have a side view mirror on the passenger side, but en route the cab has acquired one, then it vanishes again.
Continuity mistake: After Ross decides to go after Rachel, in the overhead shot all four of the cab's doors are closed, but when it cuts to Ross and Phoebe getting in and shutting their front doors suddenly both back passenger doors are inexplicably wide open, then when Ross shouts about missing seatbelts both back doors are closed again. Then when the guy gets into the back seat he shuts his door, but when he asks for the medallion number both back doors are open, and then they're closed again.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.