The One With a Chick. And a Duck. - S3-E21
Continuity mistake: When Ross is asking Joey and Chandler which suit he should wear for the TV thing the brown suit is in his right hand and the blue one is in his left hand. After Ross says "really?" the shot changes to a wide view, the two suits have changed places, and the cover on the brown suit has switched to the blue one. (00:09:50)
The One With a Chick. And a Duck. - S3-E21
Visible crew/equipment: Monica is talking to Pete in the diner when he gets back from Japan. If you look at the floor at Monica's end of the counter at the very beginning of the scene, you can see the mat that is there to protect her when she falls over later. (00:02:35)
The One With a Chick. And a Duck. - S3-E21
Revealing mistake: When Joey comes in with the shoebox containing the chick, it looks like a normal sized box, about 5 - 6 inches deep. But when Joey takes the lid off, we can see that the chick must be elevated on something inside the box, since we can see its entire body. Surely, the chick can't be more than 6 inches tall? (00:05:05)
The One With a Chick. And a Duck. - S3-E21
Audio problem: At the end of the program, Joey asks Chandler if a chick can swim. They put the chick in the bath, but it's still able to chirp even though it is supposed to be under water. (00:21:20)
The One With a Chick. And a Duck. - S3-E21
Continuity mistake: At the beginning of the episode, Phoebe gives Monica a push on her rollerskates and then we cut to Gunther giving Rachel a mug of cocoa. At this point, Monica is about to crash into Rachel, but as the angle changes we see Phoebe giving Monica a push for a second time.
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.