Full body manifestations ... 
Source: http://www.ourcuriousworld.com/TypesofGhosts.htm
The 'holy grail' of all spirit photos is the rare full body manifestation. These are images of a recognizable human (or, sometimes, an animal) in which the subject appears either partially or fully formed and usually transparent (at least in part). In some cases, the figure is clear enough to be readily identifiable by the deceased's friends or family, making them even more valuable as evidence of paranormal activity.
Full body manifestations usually appear quite unexpectedly on photos, most commonly in the background of a portrait. In some of the more remarkable examples, they can even appear quite solid and seem to be interacting with the cameraman, just as a person often does in life.
It is almost as if they are posing for a picture, as though they are either unaware or unwilling to accept their own death, or wish to continue to do the same things they did before death. There are a number of instances where the image of a dead soldier or airman appears in a group photo standing behind his still living mates, as if he refuses to break those close bonds that often exists among men who have been through combat together.
Still others, however, seem oblivious to the camera, and often appear to be about much the same routine they maintained while alive. This leads one to speculate whether the ghost is aware the camera is capturing their image, or is simply choosing to ignore it.
While it certainly seems that some ghosts are quite aware they are being photographed, there is no way of knowing whether this is true of all ghosts.
Only about a dozen really superb full body manifestation photos exist, and these constitute some of the best evidence of paranormal phenomenon on record but, as I said earlier, they will never constitute proof of ghosts simply because even the very best spirit photos are capable of being hoaxed.
They are tantalizing tastes of what sophisticated equipment might be capable of recording, but seem forever fated to remain just outside the realm of empirical evidence.
That's not to say that one day a few seconds of clear, crisp footage of a full color apparition walking down a stairs in front of a room full of witnesses may not earn a very close and serious look; it's just that scientific standards of what constitutes proof are unlikely ever to be met by a bit of flickering celluloid or magnetic tape, no matter how convincing it might be.
Image source: http://www.clevelandsupernatural.com
Source: http://www.ourcuriousworld.com/TypesofGhosts.htm