If I have Optimize iPhone Storage enabled on my iPhone and my phone storage is completely full, I understand that iOS will only store a low-res thumbnail of many of my photos on the device. (The full high-res version of the image will only exist in iCloud and on devices with Download and Keep Originals enabled.)

But when only thumbnails exist on the device, how does that work in relation to other photo apps on iOS? For example, do third-party cloud-based photo apps (like Google Photos, Dropbox's Carousel, or Amazon Prime Photos) have access to the full high-res images from the iCloud Photo Library? Or will they only see the low-res thumbnails in some cases?

  • All the apps you list seem to be designed to pull from the old camera roll idiom - photos taken on that specific device. I don't think there's a general API for third party apps to harvest originals and furthermore, my understanding is that your iOS device always downloads the full version unless and until it runs low on space. Keep that in mind if you decide to test this out on a device that's not running very low on storage space.
    – bmike
    Commented Jun 8, 2015 at 22:08
  • It looks as though in iOS 11 the full resolution photo is downloaded by Google Photos when you select an optimised image. Commented Dec 29, 2017 at 11:12

1 Answer 1


It depends on where the app is pulling images from. If you have selected "Optimize iPhone storage" then these apps will only have access to the lower-resolution thumbnails, as bmike pointed out (they use Camera Roll).

Unless the app is specifically coded to pull photos from iCloud Photo Libary (which Apple currently supports), they will just have access to the low-resolution photos stored locally on the device.

All the apps you have mentioned access your Camera Roll, therefore the low-resolution images.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .