The Bardo is a place in some Buddhist schools that can refer specifically to a state between death and rebirth, or more generally, any kind of state that is in-between two other states.
Photographs seem to occupy this place pretty well. When printed, they are actual objects that can be handled, measured, and experienced, but the thing they portend to represent does not exist at all. The reason for this might sound like semantics, but I believe it is important in our understanding of the world and ourselves, and that reason is that nothing is static. Nothing is unchanging, and a photograph depicts, or suggests, just such a state.
On a basic level, even the photograph itself is not static: colors fade, the paper yellows. This process can take a long time, but it is ongoing, and so, just like the assertion that you cannot step into the same stream twice, so too can you never experience exactly the same image. The photographic image changes and even more so, you change.
Which leads me to perhaps the more important aspect of the term, Bardo Images. When first experiencing the bardo after physical death, your karma and your training can greatly influence that experience. For some, it is an opportunity for enlightenment, or liberation, while for others it can be frightening and confusing, leading to rebirth and another round in the cycle of samsara.
So too each of us brings our experiences, attitudes and predispositions to our viewing of an image. One person can stand before a painting by Mark Rothko and be moved to tears; another can shrug and say, "it's just colors." Both are authentic responses, even as they differ wildly.
Individually of course, our reactions to a painting, book, play or film can change from one time to the next, often reflecting something gained or lost in the interim.
Mike Johnston, aka The Online Photographer, has an excellent blog entry on this topic called, "A Curious Thing About a Book." His blog attracts a lot of thoughtful people, so it's worth reading the comments as well.
Finally, this is why I believe it is important to spend time with images. Apps like Instagram encourage flipping through them at a rate approaching several per second, which has lead to a particular aesthetic I won't argue for nor against, but it has (along with many other influences)- and I think on this we can all pretty much agree - helped to shorten our attention spans.
What this shortchanges is our time spent with our emotional selves. I remember standing before a Picasso from his blue period for maybe 45 minutes as my emotions churned from awe to wonder to deep sadness to joy and back again. That process I would argue helps us to develop compassion and to deepen our humanity. Without it, we are left with a series of impulsive likes/dislikes and a growing sense of ennui and restlessness.
This is, after all, why we go through the expense and trouble of printing, matting and framing our images, and then finding the right place to hang them on a wall or otherwise display them: so we can re-visit them, spend time with them, and experience whatever emotional reactions they may spark within. So too with books we re-read, plays we re-attend, films, we re-watch. There's something important happening within us that helps shapes the way we experience the world, and we flip through it at a very real cost.
In short, the term Bardo Images is some measure of my agreeing with the continental philosophers who assert(ed) that our experience of a thing is indistinguishable from the thing itself. I think the world would be a more peaceful place if we each were more aware of the power and the limits of our perspective, and respected the same within others.
You can read more about different bardo states here.