The lab will be used for the implementation of the Open Skies agreement, that Croatia had signed.
The symbolic key to the photo lab was presented to the head of the arms supervision service, Brigadier Frane Tomicic, the Croatian Defence Ministry said in a statement.
Zimmermann said the donation was a result of the two countries' excellent cooperation, adding that Croatia had excellent experts in that field which the international community recognised.
The German brigadier general was also received by state secretary Mate Raboteg.