Iphone photo scanning?

So my dad just did the new ios update on his iphone 6 which was mine before, and it suddenly stopped working and there was a technical damage in his phone. So he took it somewhere to turn the iphone on and when he did, all his photos were deleted. So the guy was trying to get his photos back and he scanned them. And they are now downloading which says " they might take a while"

What does scanning photos mean? Can my photos from 3 years ago from when i had the phone reappear now?

There are special apps to scan photos like Shoebox and Photo Scan but this is for simple photos from old cameras.