The One With The Apothecary Table - S6-E11
Visible crew/equipment: After Rachel tells Ross that Phoebe hates Pottery Barn, when she tells him that Phoebe will be there any second and they need to cover the apothecary table, a crew member can be seen at the left side of the screen.
The One With Rachel's Inadvertent Kiss - S5-E17
Visible crew/equipment: After Monica tells Rachel that a guy from Ralph Lauren called and they want her for a second interview, when Rachel walks toward the TV and then when she stands in front of the TV, we can see a few tapes marks on the floor. One of those tape marks is also visible in one of Joey's closeups.
The One With The Fertility Test - S9-E21
Visible crew/equipment: After Chandler tells Monica the results of the fertility tests, when it cuts to Phoebe as the receptionist says good morning to her, the camera can be seen at the left side of the screen.
The One Where Rachel Has a Baby, part 2 - S8-E24
Visible crew/equipment: After Rachel asks Joey to get the other box of tissues under Ross' coat, when Joey drops the ring box then picks it up and opens it we can see the end of the hospital set floor and wall, behind the chair.
The One Where Dr. Ramoray Dies - S2-E18
Visible crew/equipment: When Chandler and Eddie are sitting in their apartment getting to know each other, there is a visible microphone in the right upper corner. (00:03:45)
The One With Ross's Wedding, part 1 - S4-E23
Visible crew/equipment: When Rachel opens the door to the apartment while she's holding flowers and sees Phoebe trying to get up from the couch (before the wedgie comment), the open edge of the set wall can be seen at the top left corner of the screen.
The One With The Triplets - S5-E3
Visible crew/equipment: In the scene with Joey filming Phoebe and Phoebe saying, "Please don't hurt me," Joey zooms out and you can see the camera that is just about to film them. (00:00:35)
The One With Five Steaks and an Eggplant - S2-E5
Visible crew/equipment: In the part where Ross is on the phone with Julie he says "Say hi to Julie in New Mexico." When everyone is shouting "Hi Julie" look above their heads and you will see a boom mic dip into the shot. (00:03:10)
The One With The Blind Dates - S9-E14
Visible crew/equipment: When Phoebe meets Joey to tell him about the date for Rach, the stage lights are seen outside the coffee-shop. (00:05:35)
The One After Joey And Rachel Kiss - S10-E1
Visible crew/equipment: After the gang leaves Rachel's room, right after she asks Joey "Are they right?", if you look above Joey's head, for a split of a second you will see a boom mic. (00:09:25)
The One With Ross's Grant - S10-E6
Visible crew/equipment: When Dr.Hobart enters the meeting room to conduct the grant interviews, markers can be seen on the floor around the first chair's wheels as well as in front of the table. (00:12:25)
The One Where Rachel Tells... - S8-E3
Visible crew/equipment: When Monica is yelling at the other couple on their honeymoon, the things on the shelves behind them shows the reflections of set lights. (00:15:25)
The One With The Bullies - S2-E21
Visible crew/equipment: While driving the cab, Phoebe is wearing a blue shirt. When the car stops suddenly, a crew member wearing a white shirt is visible driving the car.
The One Where Joey Loses His Insurance - S6-E4
Visible crew/equipment: After Rachel speaks with an Indian accent and comments on Bombay, it cuts to an exterior shot of Central Perk and inside we can see the top of the set, as well as a lighting rig at the ceiling.
The One with the Fake Monica - S1-E21
Visible crew/equipment: After Marcel has humped the chair, when it cuts to Joey walking in saying that there already is a Joseph Stalin, we can see the reflection of a crew member (presumably female) in the small mirror on the wall who's wearing a black top-and it's not Rachel, the angle is off.
The One With The Red Sweater - S8-E2
Visible crew/equipment: When Joey walks into Monica's apartment and Monica screams "I don't know how any of these got open" while throwing a box, a lot of stage lights and a boom-mic are visible above Joey's head. (00:17:00)
The One With All The Kissing - S5-E2
Visible crew/equipment: When Rachel is telling Monica, Chandler and Phoebe how Ross abandoned her at the airport, when she walks towards the TV a boom mic is briefly visible at the top left of the screen.
The One With The Mugging - S9-E15
Visible crew/equipment: When Chandler slips while wearing the shoes, if you look above Monica and Rachel, you will see a stage light.
The One Where Rachel Has a Baby, part 2 - S8-E24
Visible crew/equipment: In the very last shot of the episode, as Ross is walking down the hall, stage lights are visible at the end of the hallway.
The One With Chandler In A Box - S4-E8
Visible crew/equipment: After Joey tells Chandler he's going to his folks and might stay there for a few days while looking for an apartment, just as Joey retrieves his keys from the shelf, a crew member wearing a black shirt and white pants is visible on the left side of the screen. (00:08:40)
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.