I am getting photos from someone who is using their cell phone and sending me photos is it possible to tell if the photos were taken by using the self-timer or had to be taken by a person?
No. This is not possible. There is a standard metadata field in EXIF which tells if the self-timer was used, but:
- There's no guarantee that the cameraphone app in use actually writes this field
- Many transfer methods strip all of this off to reduce file sizes,
- It's easy to edit, so you even if it's there, you can't trust it....
- And if all of that wasn't enough, there's no way of knowing that a second person didn't activate the self-timer.