I am busy trying to find where a French distant cousin was buried, killed in action in northern France in September 1914.
In that process, I found a reference to tactical aerial photos of the day:
I cannot imagine the difficulty of the task, in the planes of the day...
Photos were 13 x 18 and 18 x 24 cm.
The photo work started in the Spring of 1915, and the pictures were relayed to the commanders on the ground.
The German armies had their own system, as well.