Backing up just photo files from Photos library A similar question was asked before but doesn't go into the detail I am looking for-
Backing up Photos library to external hard drive

I would like to backup my Photos library but I don't want to use the .photoslibrary because there appears to be a bunch of meta material. If I right-click and do "Show Package Contents" I see a "Master" folder which appears to have exactly what I am looking for. Just a folder hierarchy with all the original images. Can someone confirm if this is the case? As well, what would I be losing if I go this route?
You'll have your original pictures without edits, if backing up just the "Masters" folder.
From what I've seen, and depending on your configuration, this are some of the folders and educated guesses on what you will be losing:


Database folder: Database info on Albums,  faces, persons, and sharing history, keywords, places
There seems to be information on your iPhoto database, probably there if you upgraded from it to Photos.app as I did
Previews (which may be there if you have iCloud Photo Library as I do)
Projects
Faces thumbnails
Thumbnails