The One With All The Rugby - S4-E15
Visible crew/equipment: When Phoebe walks into the apartment while Ross and Joey are watching rugby on TV, the boom mic and a bit of the overhead studio lighting can be seen right before she sits down, and the boom mic can be seen again when Joey stands up after Chandler walks in with Janice.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.