marinwood, petzipellepingo, mistagoalie, jenelope, and adjrun all were able to name both the artist and the title; caerwynx and lilerthkwake knew the artist. (lilerthkwake said in a comment that she didn't want to mention the title in her poll answer, because she wasn't sure she was remembering it correctly, but that when she Googled it later she found out she was right.) And sunbrae recognized that adjrun used the same painting for one of her icons, which counts for something, I guess.Anyway, here's the answer:
John Singer Sargent (1856 – 1925)
Madame X (Madame Pierre Gautreau), 1884
Oil on canvas
Metropolitan Museum of Art, New York, N.Y.
The icon also serves a sort of a visual pun. I first used it for last Sunday's art post, which you'll recall was a series of photographs of Baltimore. Since that post was a combination of a list of ten things and a Sunday art post, it was only appropriate to use Madame X as the icon. Haw! I kill me.