O've seen almost every poster here, forseti... and even for those who have, I don't expect anyone to remember them all. I don't remember them all, but my brain shoots up a flare when I see something I've seen before... then I try to locate it.
Searching for things isn't easy here because not everyone uses tags in abundance... so you'd have to search from what you remember the poster was about. It's inevitable that poster pictures will be reused....
I'm more interested in plagiarism from other sites or exact copies from this one. You clearly make your posters from your own mind... I was just double-checking myself. Some users get upset when rejected "already been done" and they can't find the old one
...it's hard to find sometimes. And like I said, I don't expect anyone to remember old posters, or for that matter, never even seen them. Except for retrochop. He often gets his pictures from this site on the same day or week that they were posted.