There were images.
Found the link:
https://www.reddit.com/r/heroesofthestorm/comments/mhjnpi/a_real_leak_for_you_datamined_upcoming/
(via this post from Sami: What We Know So Far About Upcoming Events )
Note that the reddit thread was created (and seen by some of us) long before the event was even in PTR (almost a month ago actually), so it’s not a case of taking the emoji’s from the OW event and adding some made up ones for a fake leak, or something.
EDIT: I want that Sillicon and Synapse logo emoji! (even though I probably won’t actually use it 
)