This photo was sent by Tor Kiefer to his family in a letter dated August 24, 1916. Tor's regiment is fighting near the Stokhid (Stochod) river on the Eastern Front at this time, and is lying between Polish and Austrian legions.
Tor served in the RIR 249 and later in the RIR 250.
"Hab acht!" Tor writes on the back, which means "Stand to attention!"
"The German and Austrian officers in front of the altar" Tor captions this photo.
Tor's regiment joined the mass held by the Austrians on August 18, 1916, in honor of the Austrian Kaiser Franz Josef's 86th birthday. The Austrians were very pleased that the Germans participated in the mass. The Kaiser died 4 months later.
It was a Catholic mass, a "Feldmesse". A Protestant service would have been a "Feldgottesdienst".
This photo was sent by Rudolf Kessler to his family from the Western Front.
The troops are marching past a commanding officer. Rudolf served in the Leibgrenadier-Regiment 109.
Rudolf also sent this photo, which shows troops on parade and about to be inspected by a commanding officer approaching from the left.