This photo received a 4 because it shows effective evidence of imagination in its unusual viewpoint. In addition, it shows effective use of color and shape (elements of art) as well as effective use of technical skills (in focus and cropped so the entire picture plane is filled).
This photo received a 2 because few photographic techniques are evident. Usually, there is a reason to focus one portion of a photo and leave another part unfocused. Here, nothing is gained by varying the focus.
The composition of the photo is haphazard, not with intent. In addition, no element of art (line, color, shape, space, texture, value) or principle of design (balance, unity, contrast, emphasis, pattern, rhythm, or movement) stands out.