Regiment der Gardes du Corps Potsdam
Emanuel Alfred Leopold Franz, Erbprinz zu Salm
At the beginning of the war Emanual Erbprinz zu Salm-Salm was a "charakterisieter" Rittmeister carried as "à la suite der Armee" with permission to wear the uniform of the Regiment der Gardes du Corps. Erbprinz Salm was the Führer or acting/provisional commander the 2nd Squadron of the Regiment when he suffered a fatal shrapnel wound to the head on the morning of 18 August 1916. He died that night at Feldlazarett 119 in Pinsk.
from Glenn J
He is not dissimiliar to Rittmeister Emanuel zu Salm-Salm.
This definitely has nothing to do with the bottom picture. They are from different regiments. I thought they looked similar but they are not the same guy.