I'd like to say I did but this was like 8 years ago. I don't remember. Only reason I think I must have replied all is because if I only replied to the sender, I'd know who has no sense of humor.

Actually, I rarely delete my emails. I wonder if it's still archived.

EDIT: I FOUND IT!! It was just under 10 years ago. It wasn't company wide, just to our building. It was the image, not just text. And I did reply to everyone in the thread. 3 people responded to me and said it was funny. No one complained in the thread.