Apple has gone camel on its iPhones - the cameras have humps! The iPhone 7 camera protrudes from the back as does the dual camera on the iPhone 7 Pro.

It's difficult to judge just how thick the hump is from a photo, but one thing is for sure - it's a lot bigger than current iPhones have. it seems to line up with a protective case, so we're maybe looking at a millimeter.
Another iPhone 7 shell was shot from a different angle - the bottom - and there are no less than three interesting things to note.
First off, the 3.5mm headphone plug is gone. Maybe it moved to the top (there's no photo of that), maybe the Lightning port is the new destination for wired headphones. The other photo of iPhone 7's camera hump came with assurance that the 3.5mm jack is still on board (but there was no photo evidence to back that up).

Also, there are two speaker grills. Maybe one of them is decorative, but maybe, just maybe, Apple finally decided to make the jump to stereo speakers (even if they are down-firing).
And then there are the antenna lines, a thick plastic line that (used to) pass through the top and the bottom. Apple clearly went through several iterations of the iPhone 7 and there's no way to know for certain if this is what it settled on.