The One Where Joey Speaks French - S10-E13
Visible crew/equipment: After Rachel tells the others that her father had a heart attack and Ross takes two of Monica's cookies, when it cuts to the shot of Central Perk it's from a low angle, and the studio lighting rigs at the ceiling can be seen through the windows.
The One Where Joey Speaks French - S10-E13
Other mistake: When Joey auditions near the end and Phoebe steps in to explain to the producer/audition guy, she speaks French and the subtitles say, 'He is a little bit retarted' instead of 'He is a little bit retarded.' (00:18:35)
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.