Just as the photographer can only photograph from who he is, the viewer can only interpret from his own perspective, and that's a good thing, for it would otherwise reduce artwork to the status of puzzles if there was but one "solution" or meaning, and the artist to cleverness.
What then of postmodernism, which often seems to be about the puzzle, so much that sometimes the puzzle is the only way to view the photo that makes sense. Look at Richard Prince's re-photographs, for example. Visually, there is very little meaning that can be drawn unless one understands the origin of the photographs (like the "Marlboro Man" image) and then has the key to the puzzle. Without that, there is nothing. There is no other "solution," just the inside joke about advertising and imagery.
Jeff Spirer Photos: http://www.spirer.com