Steve has backed up his photos to his computer, but iTunes won't recognize his phone in Windows. His Mac works fine, though. Leo says that his iCloud sync may be on and he's run out of space. Leo has heard many "tales of woe" pertaining to Apple photos and the sync feature.
Leo recommends backing up his photos to another option like Flickr, Google Photos or even Microsoft One Drive. If he's a prime member, he can get unlimted full quality backup for free. He should download one of the apps and it will upload and back them up automatically. Apple has a bad track record with syncing and cloud computing.