Q: I just upgraded to iOS 7 and was looking forward to being able to delete duplicate photos to free up space, but this does not work. When I go into Camera Roll, select on a photo, then hit Delete, it tells me it will also be deleted from an album. Do you have any idea why this doesn’t work on my iPhone?
A: This message appears because one or more of the selected photos have been added to an album on your device.
Although iOS uses the term “Album” to refer to collections of photos you’ve created on your device, in reality these work more like tags; a photo added to an iOS album is not actually duplicated, but rather the Photos app adds a reference to the new album name and simply displays the same photo in both places.
So regardless of which albums you’ve placed pictures in, the Camera Roll remains the master repository, and therefore deleting a photo from the Camera Roll will also remove it from any albums, as there was actually only one photo to begin with. Conversely, deleting a photo when viewing it from within an album will only remove the reference to it in that album, leaving the entry in the main Camera Roll untouched.
The good news, however, is that if you’re deleting “duplicate” photos primarily to free up space there’s no need to worry about this, as iOS doesn’t actually duplicate the photos, so no additional space is taken up by adding a photo to an album.
Note that third-party apps can also add photos to albums on your behalf, although this is usually only done with photos that are created or imported by those apps. For example, a photo editing app may save any results of your edits in a specific album to allow you to easily locate them later. As with any other photos, however, these will still appear in the Camera Roll in addition to whatever album has been assigned by the app.
The only way to have photos stored in albums without also appearing in your Camera Roll is to transfer those photos to your computer and have them re-synced back onto your device from a folder or photo management app via iTunes. These photos will appear in read-only albums on your device named after the folder or collection from whence they came, but will not appear in the Camera Roll.