For the V, I don’t think you can change the image resolution.
There is no known way to remove the battery from the V and have it turn on like a webcam when the Raspberry Pi is turned on. You can:
- wake the camera from sleep with the raspberry pi
- power on the THETA V from a power off state.
Plug the camera into the Raspberry Pi when the camera is off. Then, you will see that it turns on.
I believe that gphoto2 will work with the SC2.
If you can download the files to the Raspberry Pi with the USB cable, you can reduce the file size on the RPi.
Additional examples of processing with GraphicsMagick, which is like ImageMagick.
The idea is for you to write a bash script for the RPi that uses ImageMagick to reduce the file size before you transfer it to the cloud.