An iPhone app that allow me to take a photo in the exact proportians as the last photo?

I've been looking through Google and AppStore with no luck. I'm looking for an app (free app preferred) that allows me to take a photo of myself one day, and then the next day take another in the same spot so that when I mash it together as a video it will be as if I haven't moved from that spot. Maybe one that has a stencil kind of thing on the screen I can measure my face to or something.

Other than positioning the phone in the same spot everyday, don't see this happening.

Apple sells docks for the iPhone & you could use the volume up button on the included headphones to remotely take the picture.