iOS Use of Camera API without showing viewfinder??

Would it be possible to create an app that records and stores photos from the iPad camera without showing the "viewfinder" during capture?

Specifically, I would like to create an app that takes photos when the volume up button is pressed while the entire screen just plays a random slideshow of images captured during that particular "session" of the app.

I'm assuming this functionality is either really easy or really hard, but I'm having a hard time tracking down an answer.

Thanks,

Noah