Sepia tone removed by gogm.
A re-check of this image to find a larger one on 12 September 2016 found this is the largest version available.
Dagmar wears a crinoline dress with quarter length sleeves and a bodice decorated with what appear to be buttons in this photo.
Keywords: Maria Feodorovna (1847-1928), Marie Sophie Frederikke Dagmar, Princess Dagmar of Denmark, prinsesse Dagmar, Minnie, Princess, Tsaritsa, Glucksberg family, Romanov family, Danish, long straight coiffure, chemisette, collar, bow tie, buttons, zouave jacket, pagoda sleeves, cuffs, crinoline