Hey Blogger: Why Is A Screen Shot Automatically Rejected?

A Screen Shot of my PC file system has been rejected by 

Lately, Blogger has started "screening" pictures that you insert in your blog.  And they get to decide if your picture is legit or not.  Screen shots captured by Copernicus are, apparently, not legit.  I don't know how they decide to rule out certain pictures, but it's obnoxious nonetheless.