With this add-on, when a user is banned, their avatar is replaced with a special BANNED avatar as demonstrated above.
The add-on includes the above pictured avatar. If you wish to replace you can do so at this path:
HOW TO INSTALL
1) Download the zip file. Extract its contents.
2) Upload the contents of the upload folder to the root of your XenForo installation.
3) Install using the XML file provided.