The way the person's head is framed in the shot is pretty much identical most of the time and kind of a tell on its own.
Other tells:
- steve.jpg: The skin above the top rim of his glasses has some repetition/distortion.
- customer1.jpg: Distortion in the hair, most noticeable at top left. Mouth looks fake too.
- customer3.jpg: I didn't notice anything significant, but it just looks like an image taken straight off TPDNE. Do "vibes" count?
- customer4.jpg: The teeth merge into each other.