The image is so blurry that it is difficult to resolve details.
From Wikimedia; spots removed with Photoshop amd enlarged by half. Also posted to Infanta Mercedes, Princess of Asturias’ Subalbum here.
Infanta Mercedes is turned out in a stylish and lavish wedding dress with, at least, a lace veil and a lace flounce plus many flowers.
Keywords: María de las Mercedes, María de las Mercedes de Borbón y Habsburgo-Lorena, María de las Mercedes Isabel Teresa Cristina Alfonsa Jacinta Ana Josefa Francisca Carolina Fernanda Filomena María de Todos los Santos, infanta de España, princesa de Asturias, Princess of Asturias, Borbón family, Borbone-Due Sicilie family, Princess, Spanish, curly coiffure, floral headdress, lace veil, pouter pigeon bodice, high enclosing neckline, order bows, floral bodice ornament, long close sleeves, train, close skirt, floral skirt ornament, lace flounces, fan, wedding dress