Schreyer was, and is still, especially esteemed as a painter of horses, of peasant life in Wallachia and Moldavia, and of battle incidents. His work is remarkable for its excellent equine draughtsmanship, and for the artists power of observation and forceful statement; and has found particular favour among French and American collectors. Of his battle-pictures there are two at the Schwerin Gallery, and others in the collection of Count Mensdorff-Pouilly and in the Raven Gallery, Berlin.
His painting of a Charge of Artillery of Imperial Guard was formerly at the Luxembourg Museum. The Metropolitan Museum, New York owns three of Schreyers oriental paintings: Abandoned, Arabs on the March and Arabs making a detour; and many of his best pictures are in the Rockefeller family, Vanderbilt family, John Jacob Astor, William Backhouse Astor, Sr., August Belmont, and William Walters collections. At the Kunsthalle in Hamburg is his Wallachian Transport Train, and at the Staedel Institute, Frankfort, are two of his Wallachian scenes.