This app is a fake camera shutter app, it doesn't have any photographing functions than shutter sound and flash light.

Prank shutter doesn't use camera or doesn't take any photos. Its used only for pranking.
Prank Shutter use a proximity sensor for playing only a shutter sound effect, imitating cameras shutter voice effect or sound.
This app needs a permission for flash light which is activated by the acceleration sensor. When app is on and you shake the phone, it takes about 1 second and flash light will imitate camera flash light effect, also again, no single photo or video is taken.
This app usage is only for pranking!