I agree with the categorization of the two types of posts made from that account, and I agree in theory that the J-20 2055 image is from category 1).
But category 1) does not actually indicate whether an image is genuine or not, they are just images that the account thinks is real.
Putting it another way, the issue isn't that I suspect the specific account had doctored the 2055 image, but rather whether the account had unknowingly posted a doctored image (or an image of unknown quality, for example that "submarine" image which is from the same post).
That in turn feeds into the question of why this account would be the first to post a genuine photo of 2055 on weibo to begin with. The scrutiny isn't about the account being a CGI artist, but rather the scrutiny is whether this person has a track record for being the first to release new aircraft imagery, and if they don't have a track record then why are we seeing it from them now.
Visually speaking, it is basically impossible to tell if the image is doctored or not given the quality of the image and the relative ease of doctoring it (for example, someone could have taken a genuine unreleased image of 2052 and changed the number to 2055 and that weibo account and us would be none the wiser and it wouldn't show much artefact).
That said, the idea of there being a J-20A prototype 2055 existing and flying is not at all unreasonable. But the circumstances of this image's release is a bit suspicious and is coming from an avenue that we do not usually expect.
