This is somewhat related to SWARM-I-21, while there have been improvements since that one, the core suggestion wasn't addressed.
First & foremost, the documentation needs to be updated to tell people they *must* remove the gravatar.com URLs if their server does not have access to the outside Internet. When we first deployed Swarm the performance was terrible because our server is inside a secure development environment with no external access. Every page load was delayed while the server tried to make one or more calls to gravatar.com and wait until they timed out. Quite frequently the browser would time out and give up before the page was returned, making it nearly unusable.
Second, Swarm needs to be able to manage user avatars without manual intervention by the administrator. Perforce KB 15017 describes how to use custom avatars hosted on the Swarm server, but it requires the server administrator to manually copy the image file to a directory in the Swarm installation and deleting the cache directory. There is no way for an individual user to add or edit their own avatar. This really should be a part of the user settings page where the user can upload their own image file and have the rest handled automatically.