I don't see that in mine... T-Mobile Version. Do you see the warp in the image preview while taking the picture as well (viewfinder) or does it just show up after the picture's been taken?
I have that issue on my normal S7. Actually a bunch of people have this issue. I think samsung has a software update coming out that should fix this issue.
It's optical distortion, an aspect of the S7's camera that should have been improved with the latest firmware update. I notice this on my S7 Edge as well. S7's lens appears to do this for some reason.