Photo Stitcher make long and large picture, panorama photo by take up to 3 landscape photos or 5 portrait photos by the Camera or import from the Photos then app will stitch into one large image. Stitched image looks like a photo just take from one shot from camera.
How to stitch pictures, make panorama picture: take photos from camera that having a little overlap area from one and another, e.g. take 3 landscape photos from camera (from left to right or vice versa) photo 2 must have a small overlap area with photo 1 and photo 3 must have a small overlap area with photo 2. Then app will stitch all your photos by comparing the overlap area for matching and then merging to 1 smooth picture.