Shadow People

A few years ago I was privileged to hear Chris Fleming speak at a small conference.  During this conference, he mentioned entities known as "shadow people."  Now, I had previously unheard of this term but suddenly I felt very apprehensive.  As far as I know, I have had no experiences with these beings, although I have my suspicions that I may have.  Either way, I've become slightly fascinated by them. 

Shadow People are dark, humanoid entities seen normally at the peripheral of your vision or in rarer cases, head on.  They are generally regarded as evil and leave people feeling very unpleasant to say the least.  A simple google search will pull a lot of information on them, but sadly few credible images or video.  The best video I have seen was on an episode of Ghost Hunters.  It did show a dark, shadow entity rise up out of a corridor in a cellblock and run down a walkway they were filming.  This was filmed at Eastern State Penitentiary, which is interesting considering pictures I will post below are also taken from there.

Images are worse than video, however, I have found a few images from Chris Fleming which show an original picture with a shadow person, plus the enhancements to verify the picture.

The first picture is the original, then the original which has been brightened.  The next three are a cropped image, then the image under a spectral analysis and thermal analysis.

Obviously, something is there, and it does not show any form of heat. 

So, the question is, what are these things?  I'm not entirely sure.  There are many theories but they tend to be as varied as the fake photos of them which keep popping up.  No matter what they are, I would love to catch evidence of one of them and will definitely be keeping up with any sighting I come across.