What is it you ask? Pareidolia (also referred to as matrixing) is a psychological phenomena where a vague random stimulus is perceived as significant. Examples of this would be seeing images in clouds, the man in the moon, Jesus on your grilled cheese, faces in orb photographs or figures in the shadows of trees. And it doesn't always happen with just photos and objects- ever listen to a record backwards and worry Paul was dead? We hear phrases and words in random sounds as well.
This phenomena has happened to the best of us. We take a photo in a haunted location and when we look at it we see it's filled with "faces". I have received many photos where people claim there are faces and figures in them, and I can't see it no matter how hard I look. My personal favorites are photos taken in a heavily wooded area where people see faces and figures. As hard as I try, I can never quite see what others are so excited about- even after they've outlined the area/figure for me.
So what do you do? First, orb photos are not very solid proof of paranormal activity. There are too many things occuring naturally that can produce false positive orb photos (dust, rain, snow, pollen, bugs, reflections, etc.). So while you might think that you've taken a great shot of 100 little faces in orbs, more than likely you've gotten a photo of a lot of dust and "see" the faces because that's what your brain does with random things- looks for patterns. Second, take a look at the photo, are the faces/figures part of the landscape and objects around them (like trees or tree shadows) or are they stand alone objects and separate? Obviously something that is separate from the objects in the photo deserves a better look.
Ever listen to an EVP that sounds like "blah, blah, blah-blah-blah, blah-blah" and someone else immediately declares that it's saying "What you talkin 'bout Willis?" From that point on, you won't be able to hear anything else in that EVP. Honestly, unless you have a clear Class A EVP, chances are there is no way to determine what is being said other than to distinguish the number of syllables. This is why, unless I have a clear EVP, I never offer insight on what it might be saying.
So next tim eyou're looking through your photos, take a minute to really look and think about what you are seeing before declaring great-great uncle Seamus is smiling at you from the tree trunk.