Other changes include the removal of the antenna lines on the back case, and as expected, the earphone jack has been eliminated. The source of the image says that the casing is thinner than the one used on the iPhone 6s.
The unveiling of the Apple iPhone 7 is still roughly half-a-year away. which means that we should take this image with a grain of salt. However, we should point out that in March 2014, images that were alleged to be that of the Apple iPhone 6 were leaked by a Foxconn employee. Those images turned out to be legitimate.
Also included in the slideshow along with the leaked photo, is a rendering of the back of the iPhone 7 made by an artist.
The rear casing of the Apple iPhone 7 leaks
1. Leaked image of the rear case of the Apple iPhone 7
2. Artist's conception of the back of the iPhone 7
source: NWE (translated) via AppleInsider