Yeah, there are quite a few promotional photos and viral elements like this that were released before the show aired on television. We have them all here on Fringe-Forum. Have a look around this viral forum. Here are a few to get you started:
To reference a few.
As for the connection between Olivia and the leaf, I would say that it's viral forshadowing (the poster was released before the show aired). The leaf (and the other glyphs and symbols) certainly have meaning within the context of the show. The extent of that meaning is unclear, although I would speculate that on the one hand they hint at 're-creation' (or genetic manipulation), whilst I believe that they also allude to rank and status (we've seen Nina with "leaf" necklace, for example).
I think the overall purpose of these symbols from a viral standpoint was to make viewers look and then look again. This 'double-take' effect allows us to question the way in which we view the world - an apple with two embryo's, for instance, alludes to the fruit of life, knowledge and the seed of evil, temptation as well as good old hybridization.
Just some food for thought.