The truth is that not as many as it might seem. There were about 20 bats in the room and every time one came out and cut the sensor 2 photos were taken. This year was the first day I went there and it was a session of only 1 hour (+ setting up time). It is a very precise sensor that allows us to adjust the place where it is activated and thus ensure that most of the photos have a good focus.
I have more photos from other sessions in the same place in my website (https://www.arnausc.com/lang/en/gallery/cameratrapping)