Definition from Wikipedia: is a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant.
As I have gotten more interested in the paranormal the more examples of pareidolia i have seen presented as "evidence of the paranormal". This is not necessarily deliberate but it still is false evidence.
I think its really important to keep trying to debunk everything we come across as paranormal researchers (in a kind and gentle way) not only for ourselves but the people that present us with potential evidence.
These photos are just two examples of matrixing. And they DO look like faces. But that doesn't mean that its anything paranormal.
Here's a link to a very informative article on matrixing by Grant Wilson, TAPS.
And here's a link to an article on paranormal.about about photos that AREN'T paranormal.