I'm not sure if those are actually jpeg artifacts, or simply how the picture was made. Look at the bloodstains on her mouth and shirt. There's almost no artifacting at all around those areas. I think the hair might just be a style choice by the artist.

The artifacts are smaller in those spots due to specific parameters of the compression algorithm, but they are still there; look at the white area below the shirt collar and to the right of the trail of blood on the chin. Also, most of the other works by this artist are artifacted, but none of them so badly as to indicate a 'stylistic' choice. (Although I guess you could call it 'Pixiv style', given the sheer number of artists there who are apparently blind to how ugly it makes their pictures look.)

Yeah, now that you mention it I can see the crap below the collar and around her hair's shadow on her cheek. Also in the background.

Man, this pic would be awesome if the artifacts weren't so distracting...