How it works / Installation
To check that it's working, check the profile (or other place where a user's avatar is displayed) for a user who hasn't uploaded a custom avatar. If the user has set up a gravatar account, than this image should be displayed. If not, you can right-click the "default avatar" (typically an invisible white square where the avatar should be) and choose "Copy Image URL". Paste the text somewhere and the URL should look like http://www.gravatar.com/avatar/....