It appears that for some reason this artist uploads inferior versions of his images on his pixiv account. I checked the quality of his twitter uploads and there they are better.

uohuo said:

It appears that for some reason this artist uploads inferior versions of his images on his pixiv account. I checked the quality of his twitter uploads and there they are better.

You can upload the better version and make it the parent of the pixiv version.

I have posted the twitter version