From Miss Mertens' photostream on flickr; sepia tone removed and image resized to 26.28 cm high at 28.35 pixels/cm.
This photo of María Cristina is essentially undatable. She wears a bonnet-like hat.
Keywords: Adèle, María Cristina Habsburg, Archduchess, Queen, Habsburg family, Borbón family, Austrian, straight coiffure, ribboned hat, straps, bows, coat, high enclosing neckline, collar, close sleeves