Where was this picture actually posted? Wasn't it below the one of the Fungoïd Shaman? In case it was, it's not there anymore..
https://www.warhammer-community.com/2017/12/24/new-champion-revealed-fungoid-cave-shaman/
That’s not all – we’ve got a very exciting Christmas present for you all tomorrow, and while you can’t open it just yet, here’s a hint (don’t shake it, that probably won’t end well!). We’ll see you then…
I'm confident that the wrapped miniature drawing was meant to guess the Nurgle GUO..
So I guess that we'll need to wait a couple of more days to get the AoS Order Herald..