I am generally pretty lenient about posts featuring images that are not submitted to the fanart channel. For example, sometimes users post official Nintendo art along with a comment in the general channel; that's fine. Such posts are not often featured unless they include a poll or raise a topic/question that may be of interest to the community as a whole.
If an attempt has been made to find the original creator of a work you'd like to share, but you are unable to find them, please at the very least state that the work does not belong to you. Understand that it is unlikely such a post will be featured, and the post may still have to be ejected depending on the circumstances, or in the case that the original creator asks for its removal.
As long as a user makes it known that AI was used to create content in a post, that post will be allowed to exist in the fanart channel. Please know that AI content posts will not be featured; there exist other communities for that purpose.
Giving credit for memes that were not created by you is certainly appreciated, but not generally monitored by me. Meme posts are not often featured, and they are often so viral, their origin is better documented and thus easier to find than much of the fan art that floats out in cyberspace.
My brain just went blank, so that's all I can think of at the moment. If future revisions need to be made, future revisions will be made... In the future... Whoa, that's deep.
Thanks for reading this over and dealing with my silly nonsense, hope you're all doing well, and take care!