Not being creepy would be a better start.
Data Hoarder
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
Facebook DESTROYS quality. Why on earth would you want some low quality crap? Give us more info OP. Why not ask the person for their Facebook dump file? Those separate pictures and chats so all u have to do is ask for the picture part of the dump.