Keep it civil, do not flame or bait other users. If you notice anything illegal or inappropriate being discussed, contact an administrator or moderator.
That said...ONLY UPLOAD POSTS FROM THE ARTIST'S UPLOAD PAGE AND POST THE SOURCE WHEN UPLOADING. pixiv is a favorite of ours.
If it was not found on the artist's account page then do not upload it. It is almost certainly a lower-quality version of the image and will be deleted if the original is found and posted.
If you cannot see the image on the artist's page without having to pay something then do not upload it. Patreon rewards and pixiv fanbox content are counted the same as paysite content.
Also, imgur, rule34, yande.re , Sankaku Channel etc. are not sources. Try SauceNAO to see if a better version/source for an image exists. saucenao.com/
If the image is both absurdres and uncensored, then it is quite likely paid content. If you find images that fit those criteria, do not upload them unless you can locate a source directly from the artist. Make sure to compare the files though; don't just post without checking the resolution or censorship.
If you are still unsure, message me or another moderator about it. I imagine most of us would be happy to help.