I've been going through multiple issues with iCloud Photo Library (some advice: don't ever use it) and as part of the solution I had to restore my photo library on my iMac from a Time Machine backup. That part worked, and the images are all there to see in the Photos application, but when I look at the Photo Library file in the Finder, it's now (almost exactly) double the size of the original library. iCloud Photo Library is turned off, none of the images are duplicated, the number of listed items in the application is the same as before the restore, but that file has gone from 30GB to 60GB. Any ideas?