Keep in mind, due to the TOS, there are going to be rules.
1: Do not post only the image. Spoiler something if need, maybe add spoilered context of the joke if someone does not get it?
2: Keep the images civil. We don't want a war going on in the forums because of an image.
3: Do not go out of your way to insult someone, whether it be by private message snapshots, images that insult others, or deliberately downgrading someone out of malicious intent.
4: Just have fun!
I'll leave everyone to it!