Potrace is a utility for tracing a bitmap, which means, transforming
 a bitmap into a smooth, scalable image.  The input is a bitmap (PBM,
 PGM, PPM, or BMP), and the default output is one of several vector
 file formats.  A typical use is to create EPS files from scanned
 data, such as company or university logos, handwritten notes, etc.
 The resulting image is not "jaggy" like a bitmap, but smooth. It can
 then be rendered at any resolution.