The One With Monica and Chandler's Wedding, Part 1 - S7-E23
Continuity mistake: When Monica and Chandler are talking about what his father might wear to the wedding, the door to their bedroom opens itself and then closes itself between shots.
The One With The 'Cuffs - S4-E3
Continuity mistake: Rachel is telling Chandler to break off his relationship with Joanna, who had walked through the room and went into Chandler's bedroom, shutting the door. By the end of the conversation between Chandler and Rachel, the door is open but no one has entered or left the room.
The One With The Princess Leia Fantasy - S3-E1
Continuity mistake: When Rachel and Phoebe are in Central Perk talking about the Princess Leia Fantasy, a guy in a yellow shirt and white pants is standing at the bar behind Phoebe. As they talk he walks to the door and leaves, but in the next shot he is standing behind Phoebe again, just as she says "That's the moment when she becomes a woman." (00:08:10)
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
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 the Monkey Gets Away - S1-E19
Continuity mistake: At the beginning when Rachel and Monica talk about the free coffee sample, Rachel puts it down on the counter to her right. In the next shot it's lying to her left with no time to have gotten there. After that it switches from the right to the left and back again. (00:01:25)
The One With All The Cheesecakes - S7-E11
Continuity mistake: Just after Rachel has tried to whistle and just blew out crumbs, she picks up the fork with her left hand and places it to the left of the cake on the kitchen counter. In the next shot just before Chandler picks up the cake the fork is back on the right side of the cake near her right hand. (00:16:05)
The One After Ross Says Rachel - S5-E1
Continuity mistake: Between season 4 and season 5 some of the furniture in Chandler's and Joey's hotel room is changing. In TOW Ross' Wedding the three big pictures over the beds show dark spiky plants like ferns and palm trees (as can be seen in the scene where Joey shows Chandler the video with Fergie). In this episode these pictures are completely different - they show a red flower, a sunflower and a dark green plant. The two pictures next to the door are now much smaller in bigger frames and the lamp on the night table between the beds which had a white shade in season 4, now has a black shade. The nightstand between the two beds also has a different shape.
The One With The Free Porn - S4-E17
Continuity mistake: In the scene where Phoebe tells the gang about her "Relaxitaxi" idea the position of Chandler's left arm changes between shots. In the frontal shots it's lying the back of the chair and in the shots from behind it's wrapped around Monica's shoulder.
The One Where Chandler Can't Cry - S6-E14
Continuity mistake: In the beginning of the episode when Joey tells Chandler that he hasn't forgiven him for kissing one of his sisters, Monica and Chandler's TV, entertainment set and ferns are missing from the set and there are cables protruding from the wall. The area is completely bare except for the French poster. Everything's back to normal slightly later in the episode.
The One With the Pediatrician - S9-E3
Continuity mistake: Joey's date eats the two olives from her martini, but in the next shot she suddenly has the two olives in her drink again.
The One With Phoebe's Ex-Partner - S3-E14
Continuity mistake: When Ginger leaves after finding Chandler's third nipple, she is taking her coat and her purse is lying on the counter. When the camera angle changes, the purse is suddenly in her hand.
Continuity mistake: When Rachel tells Ross that she is still in love with him, her hair keeps changing from behind her ear to down when the camera changes angles.
The One Where Estelle Dies - S10-E15
Continuity mistake: Just after the opening titles cut to Central Perk, four people can be seen having a conversation through the window. In the next shot, there is one person sitting next to the window and a waitress has appeared out of nowhere. (00:03:05)
The One With Ross's Library Book - S7-E7
Continuity mistake: When Chandler says "lie" his hand is by his side, then up. (00:07:20)
The One Where Paul's The Man - S6-E22
Continuity mistake: In the opening scene in Central Perk when Paul (Elizabeth's dad) takes Ross to one side to talk to him you can see the girl in the blue top enters the door twice: first the shot after Paul says "I'm funny like that" and then again after Ross says "I realise it upsets you".
The One Where Chandler Doesn't Like Dogs - S7-E8
Continuity mistake: When Chandler is looking over Ross' list (right before he calls him Magellan), he has the front sheet of the paper folded up. In the next shot, the sheet is folded down.
The One With All The Candy - S7-E9
Continuity mistake: In the scene where Monica's female neighbour comes begging for candy, after Monica gives it to her and shuts the door it's a man standing at the door not the neighbour.
The One Where Rachel Has a Baby, part 2 - S8-E24
Continuity mistake: When a nurse is putting Emma to bed we see that Emma is nicely wrapped up in a blanket. The shot then cuts and Emma's right arm is sticking out the top of the blanket.
The One With Frank Jr. - S3-E5
Continuity mistake: When Frank has the towel wrapped around him, the knot on his chest changes a lot between shots.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.