'Lossy'? Is that something you read somewhere? It's a bitmap, not a spreadsheet.
Jpg is a compression algorithm, it doesn't discard information, it compresses it. If you keep the compression to a minimum, when the image is reconstituted too exactly the original number of pixels by the way, not one of them is lost, some pixels may or may not be identical with the original image but is will be sufficiently accurate that you couldn't tell the difference without doing a pixel by pixel comparison with the original. More than sufficient for the naked eye at most any resolution.
Now then, if you make a jpg from a jpg them make another jpg from that jpg and keep on doing that, eventually the image will significantly depart from the original. But a first generation low compression jpg? Undetectable merely by looking at it.
Jpg is a format vastly underrated by the ignorancia.