Continuity mistake: When Nate is comforting his mother in the side room, a bracelet on his right wrist disappears and reappears multiple times.
Continuity mistake: When Angela is questioning Mrs. Fisher during lunch time, the position of her hand and the fork differ between front and back shots.
Continuity mistake: When Nate is trying to pay the mechanic, the shot from behind him shows him closing his wallet, but the next shot from in front shows him putting his credit card away, then closing his wallet again.
Brotherhood - S1-E7
Continuity mistake: At dinner, the amount of wine in Ruth's glass goes up and down throughout the scene.
An Open Book - S1-E5
Continuity mistake: When Claire is lying on her bed studying, in the long shot we see an open ring binder and open book on the bed in front of her a few inches apart. The shot cuts to a close up and the book is now on top of the binder.
Crossroads - S1-E8
Continuity mistake: During the hiking trip when Parker is about to lead the group, Claire's water-bottle disappears then reappears from her hand as she's adjusting her backpack.
Continuity mistake: Right at the end when Nate is looking at people passing by on the street, his facial hair is thicker in some shots than in others. This is because they had some reshoots, as explained by Alan Ball in the commentary.
An Open Book - S1-E5
Continuity mistake: During the scene where the four women are eating KFC, Hannah has her hands by her mouth and is not holding any food. The shot cuts, and her hands are suddenly much lower, and she has a piece of chicken in each hand.
Continuity mistake: In the first scene at the flower arranging class, the mallet held by the teacher changes position instantly between shots.
Crossroads - S1-E8
Continuity mistake: When the dance teacher is asking David out, the strap of the courier bag over the teacher's shoulders keeps vanishing and reappearing between shots.
An Open Book - S1-E5
Continuity mistake: When Nate and Brenda are kissing in the pool, Nate's hair changes between shots. Sometimes there is a section of hair dampened down onto his forehead, which vanishes in other shots.
Brotherhood - S1-E7
Continuity mistake: When Nate and Brenda are hugging after they open the gift basket, Brenda's arms go instantly from around Nate's neck to down near his waist.
An Open Book - S1-E5
Continuity mistake: When Nate and Brenda are arguing, just after Brenda sits in the chair, we see from behind that her left hand which is holding a cigarette is held up by her face. The shot cuts to a view from in front and her hand is instantly in her lap.
Continuity mistake: When Billy and Brenda are arguing in her apartment towards the start of the episode, the pendant on Brenda's necklace moves itself back and forth between shots.
Continuity mistake: When Brenda and Billy are arguing in the casino, the shoulder strap of Brenda's handbag moves from tucked under her collar in the close ups, to sitting halfway along her shoulder in the long shots.
Answer: Nate actually say "You can't take a picture of this, it's already gone." It's kinda hard to explain, but he's referring to the fact that the moment Claire wants to take a picture of is over already, and she can't take a photo of it, just a different, lesser moment.