The Wall Street Journal is reporting that the high-end 2019 iPhone could feature three cameras on the back to match some of the high-end Android phones already on the market. The current iPhone models already have two cameras on the front, a standard camera and an infrared one for Face ID and Portrait mode photos. The back has high resolution and telephoto cameras. The new camera could potentially be a wide-angle lens.
Having more cameras can also increase the quality of photos, improve features of the camera app such as Portrait mode, and give better results in low light. The image here shows a guess at what a triple-lens back may look like, though the lenses could be arranged horizontally as well which could have potential for 3D photos.