You would think they would make the instructions easier about how to do this. I did a fair bit of searching after my client posed this same exact question to me. The answer is that you have to sign up to get an account at Gravatar:
Associate your Gravatar account with all the email addresses that you use when commenting in blogs. Upload the image you want to use as your avatar, associate it with the email address, and voila…it will now magically appear next to your comments.
All avatars are controlled at Gravatar.com. Get one now, it’s much more interesting than seeing the mystery man icon everywhere.
And PS: Check out my new website https://www.awdesigns.com. After contemplating what to do with this blog, I have decided I will move it to my new website soon. Perhaps over Thanksgiving.