Visible crew/equipment: At the end of the episode when Cliff is talking you can see the end of the set, the brick wall changes to a curtain. (00:23:55)
Continuity mistake: When Claudia is saying goodbye to Sam she is holding her purse and a magazine, at first the purse is against her body, the shot changes and the magazine is.
Fools and Their Money - S4-E12
Continuity mistake: When Sam asks Woody to go into the office to talk privately, Woody has no apron on. As they walk in to the office, Woody has the apron on, which then disappears.
Continuity mistake: When Sam goes over to talk to the guy sitting at the table, the door opens and someone walks in, the shot changes and the person has disappeared.
Visible crew/equipment: In the opening scene after Sam says "I think this calls for drastic measures" there is a shadow of the camera on the wall behind Norm.
The Peterson Principle - S4-E18
Continuity mistake: When Norm says "you're right, guys don't tell on other guys" the cigar he is holding suddenly moves to the beer mug in front of him.
Continuity mistake: During the scene when Sam and Diane are left alone in the cockpit, the position of the curtain behind them keeps changing. When Sam is speaking, the curtain is half open. When the camera angle switches to Diane, the curtain is closed.
Continuity mistake: At the beginning of the episode when Diane and Sam are talking, Sam is pouring some coffee, he starts to put the coffee pot down, the shot changes and he is no longer holding the coffee pot and has started to pick up his cup.
Visible crew/equipment: At the beginning of the episode when Rebecca walks over to Norm, a shadow of the boom mic can be seen at the top of the bar. (00:04:25)
Continuity mistake: Sam puts a beer in front of Norm. The shot changes and Sam repeats the action.
Continuity mistake: When Rebecca and Sam are talking about the auction in one shot the beer in front of Norm disappears. (00:03:25)
A Kiss is Still a Kiss - S6-E10
Visible crew/equipment: There's a boom microphone visible at the top of the screen while Sam is talking with Evan Drake. (00:06:55)
Continuity mistake: At the beginning of the episode after Rebecca goes into the office, Woody walks over behind the bar and starts to talk to Sam. Carla has her hand by her mouth - the shot changes and she doesn't. (00:02:50)
Continuity mistake: When Carla hands the drinks to the costumer to bring to table six there are 3 drinks - 2 brown and 1 clear. The shot changes and now it's 1 brown and 2 clear. (00:07:10)
Backseat Becky, Up Front - S6-E25
Visible crew/equipment: When Rebecca goes to talk to Mr. Drake at the party you can see the top of the set and the studio lights in the upper left corner. (00:06:25)
How to Recede in Business - S7-E1
Visible crew/equipment: After Sam walks into Rebecca's office at the start a boom mic is visible. (00:00:50)
Visible crew/equipment: After deciding to decorate their own place you can see some mic equipment at the top of the screen. (00:06:30)
Adventures in Housesitting - S7-E11
Continuity mistake: Sam pours Frasier his coffee - he starts to hand it to him, the shot changes, and Frasier is instantly drinking it. (00:02:50)
Adventures in Housesitting - S7-E11
Continuity mistake: When Mr. Sheridan comes to talk to Rebecca there is a pencil on the bar, when he goes to leave it has disappeared. (00:04:45)
Other mistake: Right after Sam tells Carla he will sleep with the next woman who walks through the door, in the background there is an "Extra" (blonde-haired woman seen in the background behind Carla) who starts to cross right then turns and crosses left then turns right and stops and looks confused as to where she is to cross. Obviously she was given directions of which way to cross and when, but forgot. (00:04:15)
Answer: Here is the source of the "WE WIN" photo: http://www.oldnycphotos.com/nyny587ac.html Brooklyn, of all places.