Taking a closer look at the image in comparison to the iPhone 5s, they were able to determine that the display would be 5.07-inches in size diagonally. It also would have a 16:9 aspect ratio, the same ratio used in Apple's current devices.
Keeping the display ratio consistent would make it easier for developers to transition to the larger screen size and allow existing apps to be scaled up with little or no modification.
Previous rumors have predicted that Apple will release a 4.7-inch and a 5.5-inch device. Take a look at the measurements in the image below a
[via East Coast Pixels] [via AppleInsider]