Am wanting to repost an image from an artist where the only source of the image is on Reddit from the original artist. Would using that as the source be fine?
The image I'm wanting to post here: https://reddit.com/r/animalcrossingr34/comments/zwu97j/lolly_wardrobe_malfunction_gazaster/

I wouldn't, since the artist already uploaded those to e621 themselves.
post #3776050 post #3776052

But generally speaking, sure.
As long as it's a primary source, it's safe to use.

As an elaboration on what bitwolfy said, primary source in this context means (one of) the places the artist or commissioner posted the work in question directly.

If the artist themselves posts the image to reddit it is perfectly fine to use it as a source because in that case it is a valid primary source. If it was reposted by someone else that is neither artist, nor commissioner, nor a character owner it's not a primary source and thus should be avoided, as the reposter got it somewhere else in that case.