The One With Rachel's Going Away Party - S10-E16
Continuity mistake: The level of beer in Ross' bottle goes up and down between shots as he's talking to Joey at the kitchen table. (00:12:00)
The One With Rachel's Going Away Party - S10-E16
Continuity mistake: When Ross fears that Rachel is going to talk with him, the volume and the color of his beer changes between shots.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.