I recently found an image of Mayo_The_Fox in my gallery, I was looking for the link to the post on X/Twitter, but the link is no longer there. After searching, I only find the censored image on their Pixiv account. Am I breaking any rules if I upload this?

el_monstruo said:
I recently found an image of Mayo_The_Fox in my gallery, I was looking for the link to the post on X/Twitter, but the link is no longer there. After searching, I only find the censored image on their Pixiv account. Am I breaking any rules if I upload this?

If you had gotten the uncensored version from their official Twitter account, then it should be fine.
However, if the artist specifically paywalls their uncensored artwork (e.g., Patreon) and you had gotten it from some random third-party site, then it is not okay.

Also, if you have any concerns in choosing between posting Twitter's uncensored yet inferior-quality image vs. Pixiv's censored yet superior-quality image, see topic #42808.