> add quality to jpegs

Define "quality", you can make an image subjectively more visually pleasing but you can't recover data that wasn't there in the first place

You can if you know what to fill from other sources.

Like, the grill of a car. If we know the make and year, we can add detail with each zoom by filling in from external sources

	▲	hcs 6 days ago \| parent [-]
		This is an especially bad example, a nice shiny grille is going to be strongly reflecting stuff that isn't already part of the image (and likely isn't covered well by adjacent pixels due the angle doubling of reflection).