Oh, great! I somehow overlooked that community.
I see that you are mainly uploading images to catbox or using direct links of the source image. Which is fine but on the lemmy website, sometimes thumbnails are missing and some posts cannot be expanded so you have to open link in the new tab. That is the only reason why I was asking that question in my post. But it's not a big deal.

What do you think about adding a rule to have Imaginary[something] in the title just so that you could use it as a search query to find specific art, since we don't have all of those separate, specific communities?

I was thinking about having a list of possible Imaginary "categories" in the sidebar, and when someone is making a post, they could just pick one that is fitting.

This is a list from Imaginary network on reddit that I grabbed, that could be potentially used. And you would just pick one subcategory or if you are not sure about specific one, you could put a category instead.

No, the images would be untouched. And those don't really contain copyrighted characters either.

The reason to upload it directly to an instance would be just for better combability with lemmy (some image links may not show correctly on lemmy, or may be missing the thumbnail...)
On reddit, they upload it directly, and link the source.