[Bamboo Cloud docs]
[Bamboo Knowledge Base]
Bamboo is configured to support Gravatars by default. This means that Bamboo will attempt to use user's emails to retrieve profile pictures from the Gravatar service. The profile pictures will be displayed against user activity, e.g. comments, in Bamboo.
Related pages:
You must have set up an external Gravatar server if you want to specify your own server