That's exactly what it sounds to me like too. But that doesn't surprise me much, as WP doesn't support DNG/RAW at all. It's just that Nokia added support for it through a firmware update - Black, if I'm not mistaken - and that this support only means you can save the image in RAW format rather than being able to do anything else with it on your device. It's meant to have a losless image available, which can then be edited on a PC later on. If you want to edit/reframe or whatever pictures right on your device, you would have to create them in jpg instead of dng.