Am I the only one that took art a lot in school? lol Anyway I wondered, and yes, there have been unconventional portraits done before this. I read about them being described as representative, or symbolic, or conceptual portraits. Found more than I'll share but this one is from 1916 and is not a photo anything, it's a painting, but is it a portrait?
http://www.the-atheneum.org/art/detail.php?ID=154177
http://www.bostonglobe.com/arts/theater-art/2016/09/01/questions-identity-bowdoin-caOl
Or this photograph from 1920, is it a portrait? apparently the photographer, who later also did photo montages, thought it was, in representing someone. And it's not just a work by the photographer but by the person who created the subject photographed.
http://www.francesnaumann.com/ELSA/elsa05.html
I noticed there are entries that are inkjet prints, C prints, a couple of Polaroids, and one that's a print on linen, so various techniques were accepted. To me this one isn't a representation of the subject that portrays her personality or life, so in that way I don't find it that effective as a portrait. But I get the idea of it being an alternative photographic technique, and maybe the innovative aspect of it was a deciding factor. I bet there are art teachers who will be discussing this in their classes this fall!