In past, for whatever reason, when I've upgraded my phones (have gotten all phones since 4, and have alternated between fresh and backup upgrades to the new one) I seem to lose (or make unavailable) my photos on my iMac (2014 27" 5K Retina) (they show in the application with dashed outlines, but are not viewable--I have found them in my Time Machine backup, and have re-imported a few). Not sure what I'm doing wrong, but, I would like to do a fresh update (with the stuff from iCloud synching), download only the Apps I want, but to have all my photos still available at least on my iMac. What do I need to do? Thanks!!!!