What makes an interesting, perhaps even a good, photo?

Here are two recent photos, both of which I like a lot:

The first of those has gotten a bit of praise over at Facebook. I haven't even posted the second to Facebook, but I wouldn't expect it to get much attention. And yet I rather like it; in fact, I like it a lot.

But is it as good or interesting as the first? It's hard to say. The first one has rather obvious atmospherics and I assume that's where it gets much of its impact. It's a night shot, of a city, and the diffused light and softness of the photo makes it very moody. And there's that boat in the foreground at the left – could almost be a ferry on the River Styx. Whatever impact this photo gets from composition an color values would, however, be meaningless without our knowledge of what is being represented.

Here's the same image, but I've Photoshopped it in a way that preserves the composition and (most of) the color values and leaves enough of the image so that you more or less know we're looking at a city, a river, and a boat:

But most of the photo's impact is gone. The image's been flattened so there's no sense of space, no "atmosphere." And without those the composition itself is weak. Nothing there. Just colors on a surface.

What about that second photo? I won't say that it has none of the moodiness of the first, but it doesn't have much. There's some diffused light around the outdoor lamps and the door and windows of the building, but it doesn't have the pervasive impact we see in the first image. This image is organized around the man and girl (father and daughter?) in the foreground. Notice that they're out of focus; the picture's focal plane is beyond them. Can't say that's something I thought of when I took the shot; but I like it. Just who they are is irrelevant, but that they are there is central to the photo. How important is it that he is taking a photo of her? Would you even notice that? You can just barely make out the camera in his hands. To the extent that you read him as taking a photo of her, you read their actions from their positions and posture. (And I read it from what I remember of their actions while I was there).

Here's what happens to that photo when I obscure the image while retaining much of the color and imposition:

There's nothing left. The composition of the light and colors doesn't mean much if you don't know what's being depicted.