All of these examples use exactly the same source image, displayed (scaled in most cases) by the web browser.
On a Retina display, the smaller sizes show far higher detail than on a conventional display.
2880 image drawn into 1024 space
2880 image drawn into 1280 space
2880 image drawn into 1440 space
2880 image drawn into 1680 space
2880 image drawn into 1920 space
2880 image drawn into 2880 space