Windows
On Windows: Trace Bitmap in Inkscape
- Install Inkscape, a free open-source vector editor, and open the PNG with File > Open (choose Link or Embed when asked).
- Select the image and choose Path > Trace Bitmap (Shift+Alt+B).
- For a one-color icon use Single scan with Brightness cutoff; for a colored logo use Multiple scans with Colors and set the number of scans.
- Click Apply, move the traced result aside, delete the original bitmap, then File > Save As and choose Plain SVG.
Inkscape keeps the bitmap underneath the tracing. If you forget to delete it, the SVG still contains the PNG and is much larger.