After watching some ghost hunting shows on telly, I'm led to believe that they are auras from people who have passed on to the other side. They might also be stuck in limbo and are trying to get a message to you.
Do you experience sudden and unexplained drops in temperature when taking the photos? If yes, double check to make sure you remembered to get dressed. If that doesn't explain it...read on.
Do you feel chills, are they multiplying? Are you losing control? This could mean something else entirely but we can't rule out ghostly phenomena. Alternatively, you may be John Travolta. You have my sympathies if you are.
With all that in mind, if there's something strange in your neighbourhood. Who ya gonna call? That's right, Ghostbusters. Busting will make you feel good apparently.
Good luck!
I ain't afraid of no ghost!