As it turns out, the leaked photo supposedly showing off the Samsung Galaxy S6 is actually a photoshopped picture of the Samsung Galaxy Alpha. You can see in a side-by-side comparison that the fingers holding the "Galaxy S6" are the exact same fingers seen on the Samsung Galaxy Alpha photograph, and are also in the same exact position.
In addition, the fake photoshopped device looks too similar to the Samsung Galaxy S5 to be legit. If Project Zero is a complete redesign of Sammy's flagship from scratch, we wouldn't expect it to look like anything else the manufacturer has produced before.
Alleged leak of the Samsung Galaxy S6 (L) turns out to be a photoshopped version of the Samsung Galaxy Alpha
source: Toptienmobiel (translated), NWE (translated)