The term "Meme" was created by Richard Dawkins in his book "The Selfish Gene" (1976) to mean a basic unit of transmitted thought that can combine and evolve. Kind of a "mental gene". He also pointed out that it conveniently matched the common French word "meme" (thing).

This kind of meme has been around at least as long as language.

The existence of the "internet meme" was first noted in 1993, but had been circulating as part of pre-web text-based computer culture on BBS and usenet systems. Various jokes about the "Usenet Cabal" and the "Eric Conspiracy". "Confessions of a Unix Junkie" is a example of a typical text meme.

Later the term "Meme" has narrowed to only apply to images with short bits of text on them, but that violates the 20 year rule.

This is only a semi-answer to your question, but there are instances in the late 19th century of people taking photos of cats and adding humorous text to them. That means that "lolcats" date back to at least the end of the Victorian era.