>>1052450I was also thinking it was likely a doujin cover. Or at least one of the first few pages where they generally have color compared to the rest of the doujin.
Good luck sifting through every loli doujin on sadpanda, looking for a single color-page of a non-descript loli, though. If someone could narrow it down to a single loli artist, that might make it easier. As of right now, we'd have to go through more than 62,000 doujin/h-manga or 12,000 if you assume she's not from an actual work. Otherwise known as too much work.
I feel like I know the artist, but I'm drawing a blank.