Difference between a scan and a photo?

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This question popped up in my head a couple of days ago. Let me give you a little back story. I got a notification when signing into my PayPal account that because I have received a certain amount of money over the course of this year, I had to further validate the account by submitting proof of identity and address to them, in order to comply with European Anti-Money Laundering Laws.

All well and good and nothing to complicated. Submitting proof of identity couldn’t be simpler as a phone bill is a good document for that. Fortunately for me, I get my cellphone bills through PDFs online. Simple as that, just upload one to PayPal which was perfectly well accepted.

Here is where it gets interesting. I thought I was going to be a little lazy and just take a good photo of my drivers license (accepted identity proof). Apparently this was not an accepted way and I wonder if a scan of the same will indeed be accepted (we shall see).

This leads me to asking what exactly the difference is between a scan and a photo. Technically the scan is just what a photo is, an image of something. The difference to me is just that the scan is done slightly differently than the photo but the end result being the very same, an image of a document or similar that is now digitized.

What are your opinions? Should photos and scans be regarded as two very separate things or is it just the very same thing with different names?