Originally Posted by Spirit Seeker

Most orbs that you find in pictures are dust. The ones that have a grey, transparent look to them are dust. They show up in the flash because, even though they are tiny, the particles that are with a couple of inches of the camera lens will illuminate due to the flash. Rain drops, snow, bugs, fireplace ash can also show up as orbs in photos too. Bugs show up looking like little angels or pixies because they have this white glow to them (from the flash) and the wings may be sticking out.

Here is an experiment you can try at home. Take a normal flash picture of a room in your house and note the lack of orbs in them. Then take 2 pillows that have been sitting for a while and smack them together a few times. Then take another flash picture right away. You'll see lots of orbs, but these are dust orbs. Once you see them, you have something to compare to your other photos.

Now not all orbs are easily explained away as dust, moisture, bugs, etc. The ones that are possibly paranormal will show up in different colors and usually are self illuminating. Like they have their own internal energy that glows. You never see this from a dust orb.