MacRumors asked Ferry Passchier to create 3D renders of the iPhone 6 with a 4.7-inch screen and one with a 5.7-inch screen based on alleged design drawings posted by Japanese magazine MacFan last month.
The designer also placed the images of these devices alongside those of the iPhone 5S and iPad mini.
Although very similar to the existing iOS products, the future iPhones may have some unique elements, the site writes.
On the new models, the Home button goes on the left side of the upper portion.
The larger iPhone features a slightly protruding camera, similar to the current iPod touch.
The new devices come with curved tapered edges and wider and rounder corners.