First, nobody can understand why this movie is rated so poorly. Not only is this the first real horrific movie since a very long time for me who am pretty hard-boiled with a decades long experience of horror starting with driving through dark rides (ghost trains) as a child. Second, the main actress Cheri Christian has a face that lets you hope she will be the leading actress in major pictures of the future. Third, this woman is that tremendously beautiful that I suggest the directors retire all those Cameron Diazes, Eva Mendezes, and how ever the names of these ephemeral bulb-lights are. Mrs. Christian is not a light, but a sun.
However, "Dark remains" is also of considerable metaphysical importance. They idea that photographs shows creatures of the intermediary reign between reality and "imagination" that are not visible with one' own eyes is not new. But I have never seen in a movie before that those creatures are visible on the photographs only for certain people and only to certain times. This means that the photo is not just an iconic picture of reality (by which reality turns into a sign), but becomes an alternative form of reality which can change as the "real" reality can. Being a sign, the changing of the picture means that it influences the photographed objects, i.e. the sign behaves like an object. Now, in our usual world of perception, it is common that objects change signs. F.ex., if someone grows a bird, his photograph will show him with beard, not without, as it did before. But the opposite, the changing of objects by signs would imply that the photo with beard is first and only then the beard grows on the man. This is, very simply expressed, the case that happen with the photos taken by the main character in the prison, in this movie. This is new, and we must be thankful for everything new in horror movies which usually just repeat and reorder effects and features that are already well-known, mostly since the silent time.