Following support for Identicons in #120 (closed), we want to give users the possibility to use their own avatar to be recognized by their peers.
We should bear in mind the potential for impersonation, especially in forums, where users will see posts from known and unknown identities mixed together. Anyone can create a throwaway identity with the same nickname (and avatar, if we allow them) as another user, which is different from what people are used to in centralised systems.
One possibility would be to show avatars only for known/verified identities and use identicons for unknown identities and those users who did not specify an avatar.
Unverified contacts should be distinguished from verified contacts in some way. They could use different identicons or have a little badge on their image indicating the trust-level similar to the little green briar icons we use at the moment.