One important thing to consider in haunting cases is whether the content of the "replay" is related to what’s gone on in the house or on the land before the current building. It is often possible to track the "story" back to events in the current or past inhabitants' lives.
But there are other factors that may cause haunting experiences with no tie to history. One is the possibility of fluctuations in the geomagnetic field causing hallucinations that are interpreted as ghosts. Other environmentally present conditions, including standing infrasonic (low frequency sound) waves affecting the eyes. Natural plasma effects such as ball lightning and earth-lights can lead to conclusions of hauntings (and apparitions). I had a case a number of years ago in which a number of environmental conditions, from slightly angled doorways and floors to leaking methane gas from a landfill behind a hillside, caused all sorts of havoc with a family's perceptions, making them think their newly rented house was haunted.
In some haunting cases, after a time physical objects may begin to move. How can a "recording" move things? In these cases, it would appear that the PK of the witnesses' subconscious minds starts acting in play. In other words, your subconscious mind, undoubtedly picking up even more than your conscious mind is, begins to help the story along because of your expectation of what occurs in ghost cases. By expecting more to happen, more happens.
What about ghost photos in such cases? Can you take a photo of a haunt?
The same rules apply in hauntings as in poltergeist cases. Your expectation of getting something on film may allow your subconscious to use PK to put something on film.
HANGING AROUND AFTER DEATH
Finally, we come to actual spirits: Apparitions of the dead (though there are thousands of reported cases of apparitions of the living). An apparition is our personality (or spirit, soul, consciousness, mind or whatever you want to call it) surviving the death of the body, and capable of interaction with the living (and presumably other apparitions).
What separates an apparition from a haunting ghost is that idea of interaction. If a haunting is like a replay of videotape, an apparition is a video conference call. While speaking to the videotape brings no response, the conference call allows for two-way communication.
Apparitions would appear to have no particular form other than what they themselves conjure up as their own self-image. In other words, how the entity thinks of/visualizes him/herself is how the rest of us "see" the ghost.
Try this: close your eyes and get a picture of yourself in your mind's eye. That's probably how the living would see you if you were a ghost (and by the way, did you visualize yourself with clothing? Of course you did… That's why ghosts don't appear in the nude: their self-images include clothing).
The apparition communicates on a telepathic basis, our psi processes picking up this self-image and adding it to the information received by our "normal" senses. Some of us can process this telepathic input better on a visual basis, others auditory, through feeling or even on a more olfactory basis (smell). Many can experience a ghost on more than one sensory level (seeing and hearing the apparition).
The number of good apparition cases is far surpassed by the number of haunting cases, and it would appear that several things are true about apparitions.
The sheer majority of apparitions are seen once by a relative or friend or loved one within 48 hours of that person's death, as if the person is coming to say goodbye.
Most don't stick around as a ghost for more than a day or two. Longer-term apparitions tend to have a psychological/emotional need or strong desire to stay here. Such needs or desires include a denial of death, fear of "what's next", a strong desire to stay with one's loved ones, or even anger and a life cut short.
Not everyone with such strong desires or needs sticks around as an apparition.
There are likely some environmental factors that allow people with such strong desires or needs to stick around when the conditions and the psychology coincide. These factors, I personally suspect, include both geomagnetic conditions and an as yet identified factor in the physical environment.
Ghosts hang around with people in homes, offices, and restaurants and bars (gee, that's where most living people hang around). There reports of ghosts in cemeteries are extremely rare (if you were dead, would you hang out in a graveyard?).
Most apparitions are seen without any associated unusual object movement, at least for a time. It would appear that the some of the long-term apparitional inhabitants of our world, over time, learn to move objects. In other words, learning that they are but consciousness without body, they learn to use their minds to move/affect the physical world (PK), much the way Patrick Swayze's character in the film GHOST had to learn to move objects.
Magnetometers and other detectors in apparition cases are next to useless unless, apparently, the ghost is present (and generally "felt" or "seen" by someone around during the investigation). At that point, provided one has the detectors in the physical vicinity of the apparition, extremely high (and often mobile) magnetic fields are detected. In a few of my cases, we've also gotten (at the same time) high microwave readings and some unusual effects on an infrared thermalvision camera, and even what looks like energy patterns on Polaroid film.
What was happening? We're not sure if the ghost actually gave off these energies or purposely caused the detectors to detect something (that would be PK again). Or was it the PK of the investigators or experients expecting to detect something?
Can ghosts be photographed? We're back to the PK question. If ghosts can move objects through PK, they can probably affect film.
An unusual photo (or a magnetometer reading) by itself is not an indication of a ghost or haunting. One needs the very thing we use to define and study these phenomena: the experience of a human witness. That’s how we would figure out how to categorize a location as "haunted" or having an "apparition."
Otherwise, besides photographic flaws and flukes, which seem more common with digital cameras, it's just as likely (or, to my mind, more likely) that the expectations of the paranormal photographer have affected the film as a ghost has.
Many of these ghost photos are being taken in cemeteries (because a couple of ghost hunters have stated that ghosts hang out in cemeteries), even though no ghosts were ever reported in those places. Here is expectation at its height.
GHOST PHOTOS ON THE INTERNET
More and more people are getting into the paranormal proof biz; more photos and sound bites of ghostly and other paranormal happenings, supposed energy orbs, entities, and more. People accepting these pieces and making them available often do so with commentary that would seem to indicate that new advances in photo and sound technology was all that was needed to reveal all the spirits around us.
My View: Beware of ghost-hunters bearing pictures! All these new advances also make it easier than ever to fake things and to be mistaken about what one ends up with. No matter what one does, not all factors can be accounted for or controlled when taking any kind of photo, whether infrared, "normal film" or digital.
By "factors" I mean anything from problems with film (or the developing process) or the camera or the photographer or unseen influences in the environment. I've seen way too many photos with "mysterious" streaks of light that can be tracked back to point sources of light at the fringes of the camera frame (a little shaking of the photographer's hand is all it takes). With digital cameras, there’s some prevalence of flashbacks from reflective surfaces well out of range of what you see through the viewing display. Interestingly, the better the optics in a camera, the less likely one is to get orbs and other weird shapes.
Now of course, "unseen influences" can be sources of light (or heat in the case of infrared) that aren't noticed by the photographer, but they could also be a "paranormal" source. By the latter I mean anything "on the side of normal", said category including apparitions or other currently unexplained energy sources.
Finally, photos are subject to manipulation (just a people might embellish or elaborate or downright lie, so can photos). Digital photos are even more easily "edited" thanks to the ease of use of photo manipulation programs in computers.