And the page itself needs a lot of cleaning up and making things into bullet points. Long paragraphs seem formal and intimidating, I can see why some of the artists are put off.

Maybe something like:

* If you made it, or you own it, you can post it here!
(in limited quantities, free to copy/transform, go to Ao3 for archiving)

* If you didn't make it and you don't own it, you can't post a big version here.
(you can post a small thumbnail copy)