


For example, Photo Stream would save the photos automatically to the Camera Roll. Maybe, your problem to get the photos into the Camera Roll is due to using Dropbox and not one of Apple's own provided tools to transfer the photos, see the list of possibilities to transfer photos between devices. Apps are restricted to their "Sandbox", and the Camera Roll is the central sharing place for photos on iOS devices. The lack of a batch mechanism is annoying, but the restriction to the Camera Roll is built deep into the saftety restriction for IOS devices. I don't know whether to be more irritated with Apple for not providing a batch mechanism or with the app developers for restricting their input to the camera roll (unless that's an Apple requirement).
