No edit 3:2 aspect ratio

Let me make this clear – I do not want to edit the files. Is there an app that will show me my composition in a 3:2 ratio, record the picture in a 3:2 aspect ratio, and show the final picture in a 3:2 aspect ratio? I want to take a photo on my iPhone and send it directly to my printer; so that I get a 4x6 image without editing.