Simple Solutions: How to Sort Photos Into Albums AND Delete From Camera Roll
One of the most frequent complaints I hear about iOS is about how it handles photo organization. Essentially, Apple treats photos in the Photos app the same way it treats music in iTunes: one all-encompassing Library (be it for music or photos) with multiple ways of getting to the files hosted in that library (playlists in iTunes, photo albums in the iOS Photos app).
It's not a new system, but for some reason users view it differently on iOS (perhaps because so many iOS users don't actually use iTunes, and so are unfamiliar with the Library/Playlist format). The most common complaint is that a photo cannot be deleted from the Camera Roll (the "Library") without it also being removed from any album it has been placed in.
The misconception comes from the idea that putting a photo in an album actually makes a copy of that photo--on iOS, it doesn't. Putting a photo in an album is simply a way of sorting your photo so that it's easier to find--tap the thumbnail and iOS is still pulling the same image that lives in the Camera Roll. Deleting the image from the Camera Roll deletes the only version of the image, meaning, of course, that the link to that image from the Album is also deleted. Yet a great many people want photos in Albums and an empty Camera Roll.
As it turns out, Apple provides a built-in solution in the form of Shared Photo Streams. Different from the more limited My Photo Stream feature, Shared Streams allow you to create a cloud-hosted album that can contain a huge number of photos. And--this is the crucial difference--once you upload a photo to one of your streams, you can delete it from your Camera Roll. Because it's in your shared stream you can still access it from your device (in fact, you'll be able to access it from any iOS device or Mac using the same iCloud account). The key is simply this: whenever you need a new "album" for your photos, create a new Shared Stream instead. Upload your photos, and you're then free to delete those photos from your Camera Roll--they won't be removed from the Shared Stream.
Hopefully this helps make sorting photos easier for users out there who can't come to grips with Apple's approach!