[johnhiler]

I haven’t had a chance to use bbPM yet – I hear good things though:

https://bbpress.org/plugins/topic/bbpm/

This is the most popular and oldest PM plugin… it has some usability issues that are unresolved, along with some security issues (which have been largely patched, in the comments of the plugin):

https://bbpress.org/plugins/topic/private-messages/

I don’t know of any PM plugins in bbPress that allows users to send attachments/photos…