On iOS at least, apps can&#x27;t run in the background. Carousel could only upload photos when you open it (or, as a workaround, when your GPS location changes if you&#x27;ve given that permission).<p>Carousel&#x27;s &quot;Flashback -- Discover This Day in the Past Year&quot; feature strikes me as a very clever social workaround since it gets you to open the app at least once a week.<p>The Dropbox iOS app has the same limitation. Presumably you opened it more to do unrelated tasks, so it makes a lot of sense to bundle them.<p>Google Photos has the same limitation as well on iOS. I find Carousel&#x27;s syncing and Google Photos&#x27; syncing seem to be roughly on par with each other.