I think it’s unlikely to run into legal trouble. People share copyrighted photos frequently on social media, and ive never heard of someone getting hit with a cease and desist for that. If we were publishing this in a magazine, or buying ad space for it then we would definitely have a problem, but as long as we are just tweeting and sharing the image I see no issue.
Back in the days when fans would take a trade ad out in a magazine to try and save a tv show, they would use a copyrighted logo element or two.
I really need to frame my copy of this. 😉