I have been putting a Pi camera and bluetooth module into my case. The BT module receive command from my iphone and do some actions for camera module.
I can command the pi camera from my app and takes a snap shot or other commands what I defined.
I can get all photos list on my app.
I can prview all miniature of photos and choose a full size of picture to view on iphone.
The other exciting is that app can get the live video streaming from pi. App support RTP/HTTP/HLS live streaming.
iPhone is another eye for pi camera, I can take a picture and review it on the moment.