Gravatars are the universal avatar syndicated over the web.
Super easy. From Gravatar.com: “Your Gravatar is an image that follows you from site to site appearing beside your name when you do things like comment or post on a blog. Avatars help identify your posts on blogs and web forums, so why not on any site?”
There’s even a video on how to set it up and how and when they’re used:
Sign up. Add email address(es) that you use to comment or post to WordPress blogs. Add a photo (or logo) that you’re going to use throughout the web.
Lather, rinse, repeat 🙂
After signing up, you can go in and manage your Gravatar images on a whim.