Continuity mistake: In the scene where Ashley says that they've got CDs in the tanning salon you can see Ashlyn keeping a cream tube on the table with her right hand. In the next shot you see her continuing the same action with the left hand.
Continuity mistake: The position that Ian holds his nailgun changes between shots.
Continuity mistake: In the scene where Kevin and Wendy are talking outside of the school, Kevin's hair change positions depending on the shot. At the same time, each time the shot goes back to Kevin, not only does his hair change, but the people behind him. It switches from Julie and Perry to random people, then back again.
Continuity mistake: At the end of the scene where Ashley and Ashlyn are burning in the tan beds, one of them looks out of the side of their tan bed. This is supposed to be Ashlyn, but she's facing the wrong way, which means she would have to be in the tanning bed she didn't get into to make this shot right.
Continuity mistake: During the scene when Wendy is looking at her camera and Julie walks in to ask if its ready yet, you can see Wendy holding the paper with Ashley's number on it. Then when Julie walks out, Wendy turns and sees the paper on her desk, no where near her hand.
Continuity mistake: Wendy's hair in the cemetery scene changes between shots.
Continuity mistake: When Ashley is panicking in the tanning salon, her ear piece keeps moving.
Continuity mistake: During Frankie's death, right after the shot of Wendy and Kevin escaping, there is a very quick shot where Frankie is not in his car.
Chosen answer: It's metioned in the filmakers' commentary that in every Final Destination movie everyone has a premonition (Of course), well it's also mentioned by the director, James Wong, that if death wants to kill them why give them the premonition in the first place? Well he believes that there is some other force out there trying to prevent death from killing these teenagers. That's where the premonitions come in including the signs therefore, Wendy's pictures are helping signs like voices or visions from other movies. It's just the whole "giving signs" thing is portrayed differently in this movie.