Chat – shoutbox plugin

Hello,

I’ve been wondering if you can suggest a chat – shoutbox plugin which is compatible design wise with the Orizon theme.
I would like something simple, that:
– uses the wp users in order to chat
– shows the online users that participate in the chat
– allows picture sharing

Something like this would be great: http://startrekguide.com/community/viewtopic.php?f=127&t=8675

Thank you for your time.