I think I know what the differences are but thought I’d check. If I try to enable iCloud photos switch on my iOS devices it states that xxxxx number of photos will be removed because they were originally put on my iOS devices via finder iTunes. However, within the device backup option there’s a switch to enable Photo library backup. The size of the photo library is much smaller than what is show under iCloud photos. Are the photo library photos the actual pics taken or saved by the device ? It allows me to back these up whatever they are and doesn’t remove my thousands of photos that were originally imported to my device via iTunes. Cheers