Gravatar is a free service, which enables you to associate your e-mail address with an image. Having an account and entering the appropriate e-mail address when creating an article, will enable the display of your author thumbnail. You can sign up to Gravatar here: http://en.gravatar.com/
After entering your e-mail address, Gravatar will send you a confirmation link, which, when clicked, will allow you to add your picture. Please note that it can take up to a few days for services to fully register your new image.
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