How it works
The SVG markup is drawn onto an HTML canvas at the size you choose, then exported as a PNG. This is the same rasterisation a browser already does to display an SVG on screen, just captured into a downloadable image instead.
Choosing a size
SVG has no fixed resolution — it scales cleanly to any size. Width and
height default to whatever the SVG itself declares (or its viewBox, if
it has no explicit size), but can be set to anything to render a larger or
smaller PNG.
Common uses
Generating a raster fallback or favicon from a vector logo, or turning an icon into a PNG for a context that does not accept SVG.