I'm sorry if a similar question has been answered before, but I am stumped. I recently bought an artist CG CD because I could not find it anywhere after a VERY extensive search to find it online. Now I am wanting to upload it, but am confused as to what I should do for source. The artist has a pixiv post showing the CG on sale from 2015, so would that be the source I'd be tagging? It doesn't have any complete images from the CG, but I can pull those from the CD itself.