These are the steps to follow in changing your profile picture on your WordPress website and any other site that uses your email address:
Visit www.gravatar.com

Navigate to “Create Your Own Gravatar” and click on it

Enter the email address that you use on the WordPress site

Enter your username and password and hit sign up

A confirmation email will be sent to the email address you used

Check the email and click “Activate Account”

You’ll be taken to the gravatar site again

Hit “Sign in to Gravatar”

After signing in, scroll down to where it says “Add a new image”
Hooray! You just added a photo to your wordpress account / email address / your wordpress website and most other online profiles that require that specific email address.