Someone on NeoGAF also had a nice theory, however I think it's still rather unlikely.
The image isn't a Demon's Souls remaster hint, it's a Bloodborne 2 hint. The picture is showing the PlayStation exclusive history of the "Souls" games. On top where it all started: Demon's Souls. Below that: Bloodborne. Then Bloodborne: The Old Hunters and finally the 2 Bloodborne copies on the bottom, which represent Bloodborne 2.
http://www.neogaf.com/forum/showpost.php?p=186980231&postcount=287
But yeah, I'd agree that if this is hinting at something it's a Demon's Souls remaster, I doubt we'll see anything about Bloodborne 2 at E3 at the very earliest.