Just acquired an important nugget of Doom history - a copy of the July 1994 edition of Wired Magazine. It includes this one page article with a photo of Jay Wilbur, John Carmack and John Romero that is the clear source for the "Romero's head" sprite.
Romero commented on my discovery: https://www.doomworld.com/forum/topic/106859-the-source-image-for-romeros-head/?do=findComment&comment=1999984
This reminds me that I need to get around to reading Masters of Doom one of these days.
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