it is the head of this piece from the Oceania collection at the St. Louis Art Museum: https://www.slam.org/collection/objects/7675/
the next obvious question is "why" and the answer is "i went to the st. louis art museum a few weeks before i first set up my website way back in 2009 and since this picture i took was in a folder on my desktop and i liked how it looked i used it as a background image on the page and as a favicon, then changed the background at some point later but never got around to changing the favicon because the notion of a personally hosted blog died not longer after i made one"

