I sent u an email a year and a half ago regarding jpegartifacts. Go check that out Battlequeen

One way u can REALLY tell tho is ok, like for example, get a clean png and then the same pic but in highly compressed jpeg format. IF u have a laptop, push ur laptop screen back and like look at both pictures from like, the corner of ur eye. You’ll see the difference. I feel like I explained bad but whateva.