@designsimply,
First of all, thanks for the response. The link you provided was very informative. Unfortunately, it seems either too generic (or more likely) too advanced for my current level of css skill.
I was able to "inspect element" of the "anonymous" name via chrome. Here's what I came up with:
<div class="author">Anonymous</div>
I'm sure this is what I need to edit, change, or modify. Your link may have helped a more html savvy person figure this out, but I'm still a bit lost. Any more assistance in narrowing down how to change this element would be much appreciated.
The MonsterID is a great backup if I can't figure out to pick a specific icon for anonymous users. There's got to be a way to insert an image though . . . once I figure out what specific element I'm trying to modify and how to change it the way I want.