Because ghost hunting isn't an exact science, the debate will continue to rage on and on, with neither side backing down.
However, if you're familiar with basic photography and weather elements, you can at least use these to your advantage when debunking photographs.
Dust is not your friend in photography. It leaves little specks all over your photos and basically ruins them. Also, dust can catch the light and create "orbs" in your photos. Dust is in the air. It's everywhere. When you walk through a room, even after you've just cleaned it, you will kick up dust. Dust is, also, mainly just skin cells. So, dust is you and everyone you have passed on the street. And you're breathing it in. Just to put that note in there (this post isn't scary, so I had to put some fear in you).
Ask yourself this when you see an orb in your photo: "Is my lens clean?" and "Did someone just walk through the area where I shot the picture?" or "Did a breeze just blow through?"
If you answered the first with a positive, then the next two with negatives, you're probably on to something.
Remember, dust is small. If you capture something large in your photos, it's probably not dust.
We always recommend people to take multiple pictures in a row. Chances are, if dust was blown up from the wind or someone walking, you would capture it in numerous photos, not just suddenly in one and not others.
Now, how's the weather? Is it very humid? Is it raining? Moisture in the air can create what looks like orbs in photos, as can a flash hitting a raindrop (like the above left photo).
Don't use your camera phone. I can't stress this enough. When we ask people if they have a camera and they reply, "On my phone," we will generally give them one of our spares to use for the night. Camera phones have very little range on them and the flash is incredibly bright and harsh. Though the brightness may help in the dark, and to give you premature blindness, it's not formulated like a digital camera's flash to adapt to the surroundings. Therefore, it's like someone suddenly lit up a floodlight for a second while the shutter snapped. Because of this, the light reflects off of everything and leaves mists and orbs from anything in the small radius it hit.
What's inside your orb? That might sound like a silly question, but a lot of time, true orbs will have faces in them. Think this sounds weird? Well, think about it, an orb is a person's spirit manifesting. Doesn't it make sense you might be able to actually see their face?
Does your orb have color? If you're in the middle of an empty warehouse, and all of a sudden you capture a red orb, doesn't that seem a bit strange when there's nothing red around you to reflect from? Brighter orbs are generally thought to be "spirits" more than lighter ones.
Again, these are just guidelines and again, this isn't an exact science, and one person may say one thing while another something different. In the end, you decide. It's your photo, your investigation, and your experience.