I would say that a "photograph" should represent the content captured by a camera. A photograph requires a lens, a camera (box), and a light sensitive plane. It does not require a darkroom or a computer. The purpose of processing is to improve the photograph and make it a useable format. You don't create a photograph in the darkroom.
If the meaning of the original content is lost, it ceases to be a photo. This alteration could be done in a darkroom using "traditional" techniques or in a computer. For Example: using scissors to superimpose your Nessie toy onto a negative of your local lake completely changes the content from what the camera created. Now it's a photographic composite. I think that the image in the OP's post is in the same category.
There's a weird loophole in this definition:, in-camera compositing. If compositing occurs in-camera, before processing, it still fits the definition of a photograph. Double exposures on film are a good example. The question then is: what about digital? The term "before processing" gives us the answer. Digital cameras also contain mini-darkrooms of sorts, so it's tough to tell if the image was created by the lens/box/sensor combo, or in processing. If you could double-expose a single RAW file, it would fit the same definition as double exposure on film.
I also think that when an artist washes photographic prints in strange chemicals causing the colors to bleed and create abstract patterns, that he is creating "visual art". The image created by the camera is completely lost in abstraction.
I had never thought of my blade logos as photos, despite the fact that I started with a photo. Though, by a broad definition, the first logo does qualify as a photographic print. I have no experience in graphic design, so in both logos, I had to use the same photoshop commands I use editing photographs.
As far as our art goes, this definition doesn't matter. But it does affect our perception. That's why we have words like, "photograph", "painting", "rendering", and "drawing". The visual results could be identical, but the way we arrive at that result matters. It says something about the artist. Take a look at the reactions a photo-realistic painting gets. It would would have been easier just to take a photo, in fact, the artist probably started with a photo as reference. It's the time and skill that the artist applied to the painting that really impresses, even if the finished image is identical to a photograph.