Samsung phones always take excellent pictures. I had an s6 before my current phone and was pleased with image quality. From the reviews I've read, it still looks like the S7 beats the P9 in camera performance. Granted, I don't think you'll be disappointed in either phone.

With that in mind, they'll never be able to replace a true DSLR. Even my $200 Olympus mirrorless takes vastly better pictures than any phone I've owned ever could.