I believe this is the same dress seen in the last image where Eulalia is with her son; attention is paid to the sleeves and bodice of her dress.
Keywords: Infanta Eulalia, Princess, Borbón family, Borbone family, Spanish, straight coiffure, jeweled headdress, scoop neckline, epaulettes, lace, quarter length close sleeves, blouson bodice, waist band, natural waistline, close skirt, over-skirt, necklace