The One Where Everybody Finds Out - S5-E14
Visible crew/equipment: When Rachel stands up to get laundry for Monica, a stage light can be seen in the TV. (00:07:20)
The One Where Everybody Finds Out - S5-E14
Visible crew/equipment: When Ross is using the binoculars to watch Ugly Naked Guy's apartment, the end of the set wall can be seen behind him.
The One Where Everybody Finds Out - S5-E14
Visible crew/equipment: When everyone's looking out Monica's window into Ugly Naked Guy's apartment, and see all the gift baskets he's been sent, the end of the set wall in Monica's apartment can be seen.
The One Where Everybody Finds Out - S5-E14
Visible crew/equipment: While Phoebe and Rachel are at Ugly Naked Guy's apartment, when Phoebe looks out the window and sees Monica and Chandler the end of the set wall in Monica's apartment can be seen.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.