The One With Ross' New Girlfriend - S2-E1
Deliberate mistake: The door to Monica's bedroom is open in many shots, such as when Ross introduces Julie, and we can see that there's a wall (with a framed picture) directly opposite the doorway, but when Phoebe's giving Monica the haircut they're in Monica's bedroom and there's no such wall in front of the door.
The One With Ross' New Girlfriend - S2-E1
Other mistake: After Rachel takes the phone from Ross and hangs up on Julie, when she's sitting at the table there's a bottle of Evian water in front of Monica with part of its brand name covered - the letters "e" and "n" are whited out leaving "via" on the bottle.
The One With Ross' New Girlfriend - S2-E1
Revealing mistake: At the end, when Rachel and Ross are talking on Monica and Rachel's balcony, the edge of the "brick" wall behind them has a gap in it. The facade is obviously a thin plastic sheet made to look like bricks and mortar, and it has pulled away from the surface it is attached to.
The One With the Breast Milk - S2-E2
Continuity mistake: At the start of the episode when we first see Carol breastfeed Ben, Susan puts a pillow under Ben's head twice. (00:00:30)
The One With the Breast Milk - S2-E2
Visible crew/equipment: In the first part of the episode, there is no ceiling above the secret closet, revealing a whole lot of stage lights. (00:01:20)
The One With the Breast Milk - S2-E2
Other mistake: After the opening credits, the clip of cars driving at night in New York is played backwards. (00:02:39)
The One With the Breast Milk - S2-E2
Continuity mistake: When Ross thanks Monica for going shopping with his new girlfriend, Monica has her arm up, and the camera cuts, the arm is down with no time to do so. (00:04:00)
The One With the Breast Milk - S2-E2
Continuity mistake: When Phoebe tests then tastes the breast milk, Ross is holding Ben. Every time the camera goes back to Ross, the baby has his dummy in, then out, then in again, but no sight of Ross putting it in his mouth.
The One Where Heckles Dies - S2-E3
Continuity mistake: When the gang and Mr Treeger watch the paramedics take Mr Heckles away, a thin dark object like a camera mark or a pencil suddenly appears on the floor close to Ross' feet. (00:03:25)
The One Where Heckles Dies - S2-E3
Continuity mistake: After she breaks Rachel's seashell lamp, Monica puts her jacket over the back of the big chair. When Chandler sits on it, the jacket keeps disappearing and reappearing in almost every shot. (00:17:35)
The One Where Heckles Dies - S2-E3
Revealing mistake: After Mr. Heckles has been taken away, in the last wideshot while everyone's still standing in the hallway, when this is viewed on the DVD (Warner Bros. S2 set) we can see a long black line on the floor (as noted in another mistake). The problem is that when this is viewed online on Netflix, even though we can see the very same area of floor, that black line has been blurred out. Weird that it wasn't edited on the DVD, and yet it was for the version available on Netflix.
The One Where Heckles Dies - S2-E3
Visible crew/equipment: When Mr. Heckles is being taken away, just as the officer starts to follow the gurney the shadow of the moving boom mic can be seen on the wall behind him, at the right side of the screen. (Widescreen version).
The One Where Heckles Dies - S2-E3
Visible crew/equipment: Right before Monica breaks the seashell lamp there's a shot of Rachel walking into her bedroom, and just as she walks through the doorway set equipment can be seen at the right side of the screen. (Viewed on widescreen).
The One Where Heckles Dies - S2-E3
Visible crew/equipment: After Mr. Heckles is taken away, when it cuts to Phoebe walking out of the kitchen, the reflection of studio lighting array can be seen on the TV screen. Also later in Heckles' apartment, studio lighting's reflected on his TV screen.
The One Where Heckles Dies - S2-E3
Visible crew/equipment: After Monica yells "Stop with the broom, we're not making noise," when both Monica and Rachel stomp their feet the studio lighting can be seen at the top of the screen, over Ross (this doesn't refer to Monica's star light fixture). And when the others join in stomping their feet, we can also see the boom mic dip into view.
The One Where Heckles Dies - S2-E3
Continuity mistake: After Monica breaks the seashell lamp, when Phoebe says that she wants to believe Monica did it accidentally her right is arm up and points to Monica, but in the next shot it's Phoebe's left arm that's up while still pointing at Monica.
The One With Phoebe's Husband - S2-E4
Continuity mistake: In the scene where Rachel is telling Ross it is sexy for a man to wait before having sex, the cups behind Ross change color: red to green to red and back again. (00:08:10)
The One With Phoebe's Husband - S2-E4
Visible crew/equipment: After the opening credits, just as Joey says that it's unbelievable Phoebe can be married, a camera and yellow electrical cord can be seen at the left side of the screen, and a bit of it is still visible in following shots when Monica mentions the cheeseburger.
The One With Five Steaks and an Eggplant - S2-E5
Continuity mistake: When Chandler picks up the phone, he says "Bob here" and Ross is sitting by the bar on the living room side. When the scene starts again after the credits, Ross is getting a drink out of the refrigerator. (00:01:00)
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)
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.