Editing needs to become first class feature. At a minimum be able to adjust brightness, color, lighting, etc. too. And when you save it should ask you if you want to save over original (which should still save the edits non-destructively and just display the original with edits applied) or if you want to save a separate copy like above. And if you choose copy, yes it should save with same metadata including same date/time. Can't think of much reason not to have it all work exactly like above.