Crim, Conspiracy
Given the general mens rea of conspiracy, asynchronous contact on computer bulletin board suffices for actions "in concert" as required by the statute.
Active participation on a bulletin board suffices to prove furtherance of the board's common goal.
Communication with a closed community can constitute advertisement.
Where victim was harmed by both image and subsequent viewing of image, restitution must be disaggregated.
USA v. Steven Grovo
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.