Is it possible to add an image or plot output port to a meta node?
you can add an image port when creating the meta node. Simply select all nodes that should be inside the new meta node and select the “Collapse into Meta Node”. The meta node will have as many out ports of any type as connections to nodes outside of the newly created meta node. In order to add an image port to an existing meta node expand the meta node first via the context entry “Expand Meta Node” add an image connection to node outside of the meta node and recreate the meta node as described above.
Fair enough I've used the workaround as well. However, I must admit that having all port type at your disposal when manually adding ports would be convenient. :-)