Greetings,
Somewhere in my files is an article--IIRC, from an old issue of The Mariners' Mirror,
It is noted therein that a number of popular Jolly Roger depictions were derived from an undated file in the National Maritime Museum which were reprinted by Philip Gosse in the '30's.
If it were me, I'd look askance at any depiction of a Roger that did not derive from a known primary source.
Wynne's flag IS from a p.s. though.
Regards,
Corsair