I've been over these before in my post about spirit photography and most people wouldn't give any credence to them anyway, so I think I can skip these.
In a recent conversation with Bryan Bonner of Rocky Mountain Paranormal, he informed me of the dismaying fact that orb photos are making a come back. Now, I can explain what causes these anomalies, but the likely reply would be that the photographer can tell the difference between dust motes and a "real" spirit orb. So let me offer this; In the real world, no form of energy floats around in blobs or spheres and the only energy you might find escaping a dead person is heat. So what are these things, if not bugs, dust or moisture? Any other explanation should be considered special pleading. Some non- falsifiable idea that someone made up to perpetuate whatever belief they've created to make themselves feel good and special.
Suppose you've come across a picture that doesn't quite fit into the aforementioned categories, what can you do? First off, whatever your gut might say about it "not looking right" or if you can " just tell" carries no more weight than any paranormal proponent boasting "I know what I saw". You might not be able to identify whether a picture is legitimate or not, but there are a few tips for judging the pictures source.
First of all, be aware that any paranormal group touting that they use the scientific method in their investigative process is committing a fallacious appeal to authority and is inadvertently revealing their misunderstanding of science. This claim does not add credibility to any form of "evidence" they might offer. Remember, in order for their investigation to be a legitimate experiment, they must first form a falsifiable hypothesis. Is the existence or presence of ghosts falsifiable? No. That house of cards falls apart faster than it's being built.
Second, you should question their scrutiny of their own evidence. Many groups claim to take their photos to experts for analysis and return with what looks like a Warhol print of "photoshop detecting filters". When the picture inevitably passes this test, they can then claim that it "baffles the experts!".
Here is an example: http://www.lakelureghost.com/Proofing_the_Picture.html
You might recognize this as the motion blur picture from my previous post. This effect was created in-camera, so even if the mentioned "photoshop detecting filters" were in any way affective, they wouldn't apply to this case.
Here I have taken a Photoshopped image and run it through the same process, which is really only adjusting the levels and curves, and in no frame is it more apparent that the image was altered.