I think it should be a rule that a comment should be added in order to explain exactly what meme/fad/design originated from the post, this way it is also possible to remove pictures erroneously added.

There's also something to be said about it being objective and not subjective. It could be a tag, but a pool is definitely better and makes more sense imo.

Strange, I always just assumed that this pool already had a rule like that, like pool #4068 or pool #5960. Not that anybody ever actually bothers to follow those rules.

+1 to updating the description anyway.

+1 about the description change but -1 to the comment ruling. Not enough people look at the rules if any, besides I think the tag referencing the trend plus its inclusion in the pool itself would be more than enough to give out that it's the birth of something.

I think a rudimentary but effective alternative would be to add a note to the image saying something like "Posted in xx/xx" or "This is the start of [whatever]" similar to a TL note on 4koma and comics.