What size will my PNG be, and can I change it?
The size comes from the SVG's width and height, or its viewBox if those are missing or in percent, and falls back to 300×150. The Output size choice above the upload box makes it 2× or 3× that size; for an exact size, edit the width and height on the SVG's root element before uploading. The longest side is capped at 8192 pixels.