The first impression that came to my mind, is how each falls in love with the other... with who the other is at that moment. Then, as time passes and people change, love changes. It never seems to be what it was... because we aren't who we were. Love, was that moment. An instant picture developed at that time.
According to the song... apparently love is a Polaroid because that represents a still image and it rhymes with void., which was the point of that chorus... that love is better in the memory, and the memory isn't enough to fill the feeling of emptiness.
That's my take anyway.
