The One With The Embryos - S4-E12
Continuity mistake: At the end, when Monica asks about the garbage bags the apartment's front door is closed, but when Rachel opens the drawer and freaks out about what's inside, the front door is wide open (for the camera) as she kicks the drawer shut, and then the door is closed again. (Widescreen).
The One With The Embryos - S4-E12
Visible crew/equipment: When Rachel crosses the boys' apartment to see what is in the drawer, if you look up to the right, you can see a glimpse of a boom mic. (00:20:25)
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.