Now that the Google Photos Backup (desktop uploader) app sent my entire Photos library to Google's cloud, I figured I'd check out the Google Photos app for iOS, and I turned on its "Back up & Sync" function. I wanted to see if I could get it backing up via LTE (since iCloud Photos only backs up via WiFi.)
Well, my iPhone's Google Photo attempt at "backing up and syncing" my iCloud Photo Library on my iPhone ended with a bit of a fail, on a few fronts.
For starters, it never actually finished. It took many days to work through my ~25,100 photo library. It finally got down to 10 remaining today, and I watched with anticipation. I wanted to see it finish! I wanted to see how it would behave next. Would I be able to backup new photos via LTE? And how would those sync to Photos later when on WiFi? How would deletions from Google Photos be handled? Would they sync back to Photos? So many questions.
Well, I never got that far. It stopped at 10 photos remaining and refused to continue. I stopped the sync and started it again, I force quit the app, I restarted the iPhone. Over the course of many hours, I somehow managed to get it down to 7 photos remaining. But try as I might, I could never get it to go beyond those 7. Argh. So frustrating.
All along the while I should also mention, that there were a few photos in Google Photos I had inadvertently deleted. I only noticed this when I saw them first missing in Photos for Mac. So I recovered them in Photos for Mac. And then a few hours later, I saw the "Do you want to sync these deletions" on Google Photos on my iPhone. I thought that was odd, so I didn't confirm the deletion. After all, I wanted to preserve those photos! So I swiped away the card. Sure enough, many hours later, the "do you want to sync these deletions" alert came back again. And it would keep coming back, many times, over the course of two days. It's as if it had "cached" this deletion request, and refused to let go of it. Ultimately I just confirmed the deletion sync request, and then recovered the same photos back in Photos for Mac (again) and then I exported them from Photos, renamed them in the Finder, and imported them again... hoping Google Photos would see them as different photos, and not bug me about syncing that old, inadvertent delete request yet again. Yeesh. I don't know if those 5-6 photos were part of the 7 that Google Photos was unable to sync, or what. I just know that by this time, I was really frustrated by it all.
All the while I would get iOS prompts that my "storage space was almost full" -- even though when I went to Settings -> General -> Usage to check, it would show I had 14+ GB free. I would sometimes see that the amount of storage that iCloud Photos was using has increased dramatically, but then it would decrease just as much shortly thereafter, all on its own. So I do believe Google Photos was downloading the full photos in order to upload them, but then iOS was purging the full photo in favor of an optimized version (or thumbnail) per my Settings. It certainly felt like a lot of "heavy lifting" was going on, and I'm not sure it was all worth it. I also got the distinct feeling that, much like the Google Photos Backup (desktop uploader) application, it was written with iPhoto and Photo Stream in mind, for folks with only the most recent photos on their phone. And NOT for iCloud Photo Library, which is effectively someone's entire photo library. And I think Google Photos was struggling to make sense of this very large (and not entirely local) library, and how to "backup and sync" it all. I don't think it was engineered with this new Apple service in mind.
The final disappointment came when I tried to troubleshoot, these last remaining 7 photos that refused to backup. So I toggled off "backup and sync" in the Google Photos. (I might have also deleted the app and reinstalled it, I can't remember -- it's all a blur.) What I do know is, I saw the Assistant show me its progress, and it was starting all over, at ~25k photos to backup. Noooo thank you. I toggled it off again, and won't be using Google Photos to backup and sync my iCloud Photos from my iPhone for a long while again. I'll just use the desktop utility to upload to Google from Photos for Mac, and the iOS app to check on things. Given my experience with the persistent (and unwanted) deletion sync request, I'm sure I'll even be treading carefully with that, as well.
Anway, sorry for the long post, but I just wanted to share my experiences for the benefit of anyone else who is tinkering with these same specific ingredients.
