Currently, the Activity Stream retrieves the avatars for the updates depending on the application which Application Links are set.

For example, the user has set a custom avatar in JIRA, but is using the default avatar in FishEye.
In the Activity Stream, sometimes the user sees his JIRA avatar, and sometimes his FishEye avatar. This is dependent on where the update came from. If the update came from JIRA, then it will show his custom JIRA avatar. However, if the update came from FishEye, then it will show the default FishEye avatar, even if it is the same user in both sides.

This could cause some confusion. It would be useful if the user has a choice to determine the source for Activity Stream to retrieve avatars, for example to only take the avatars from JIRA.