Why might my guy friend take candid photos of me on his phone?

Like while I'm asleep on the couch or not paying attention at lunch? They aren't creepy (I've seen a few--they are focused on my face, not my boobs or anything). Even though he isn't obvious about it/does it secretly (I found out by accident), I am not actually creeped out (he is a really close friend and we call/snap/text/hang out a lot). I'm just curious.

I have an idea, but I'm not sure if my own feelings are influencing me. Lol
Why might my guy friend take candid photos of me on his phone?
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