I e-know a few of these people...for how long varies from several years to a few months. They are used to seeing my milk carton avatar dancing back and forth, so I don't know if the still photo is going to fly with them.
I hereby present photographic evidence not only of our existence, but our interaction to boot!
Proves nothing, solipsism and all that. One objection that might possibly be raised here is that figments of my imagination would likely be wearing considerably less in the above photograph. But I counter with the notation that my subconscious is stubbornly Catholic even as conscious mind has moved on.