The One Where Ross Got High - S6-E9
Continuity mistake: When Ross finishes the trifile, a small amount of whipped cream appears and disappears throughout a few shots. (00:16:35)
The One Where Ross Got High - S6-E9
Continuity mistake: When Ross asks Rachel to step into the hallway, we see the whipped cream atop the trifle dessert plates on the table, but while Joey gives everyone acting lessons all the whipped cream is gone, then the dollops of whipped cream reappear once again.
The One Where Ross Got High - S6-E9
Continuity mistake: When Rachel tells Phoebe that she's making a traditional English trifle, Monica's holding a cloth napkin, but in the next shot the napkin's suddenly gone and she's now holding forks.
The One Where Ross Got High - S6-E9
Continuity mistake: When Phoebe finishes telling Rachel about her thanksgiving dream about Jack, Chandler is looking straight ahead with his arms crossed. Cut to the next shot when Jack and Judy are coming out of Monica and Chandler's room, and his arms are immediately uncrossed and he's looking at the women. (00:20:05)
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.