Somehow chanced upon this site (http://en.gravatar.com/) which allows you to set a custom avatar, so that when you comment on supported platforms like WordPress, it appears along with your comment. Neat huh?

How you use it is like this:
1. You register for a Gravatar account.

2. You tie one (or more) email address(es) to that Gravatar account.

3. You upload avatar(s) into your Gravatar account.

4. You tie the avatar(s) to the email address(es) in Gravatar.

5. Go to the (WordPress) blog post and add a comment. You need to fill in the email address to be the same as one of those you registered into Gravatar.

6. The corresponding Gravatar appears along with your comment!