Why was the pixiv post reduced to the child post, they're the same res and the pixiv one is a slightly larger size than the twitter one?
Score preservation? Anyway, there's no reason why the Pixiv version should be the child. It's almost never the ccase that the Pixiv version is worse, even if the Twitter is a PNG file.
Seulbae changed all the pixiv ones for this same artist to be children of the Twitter variants before that were the exact same situation as this... why's it all of a sudden any different of a situation?
And I even had another user (CodeKyuubei) say to do this as well.
I changed the parenting because the images seem to be straight re-uploads of the twitter image to pixiv by the artist, with the slight difference in file size because of pixiv re-encoding the image.
Thus, in terms of both compression guidelines and first-to-the-post relations, I'm sure the twitter images should be the parents.
Edit: That is to say, the artist is not uploading the source image separately to twitter/pixiv, he's uploading the twitter image itself to pixiv.
So from this point onwards it should be considered superfluous and not worth uploading pixiv images without a significant size upgrade, if not outright spam?
If he doesn't change how he uploads to pixiv, then yes I'd consider it superfluous.