Basic Encoding
The encode function and the toArray function are all you need. See Example.hs. You can use ImageMagick/GraphicsMagick to enlarge the symbol and convert to other formats:
$ runhaskell Example.hs
$ # ImageMagick
$ convert hello.pgm -bordercolor white -border 4 -scale 300x300 -interpolate integer hello.png
$ # GraphicsMagick
$ gm convert hello.pgm -bordercolor white -border 4 -scale 300x300 hello.png
Output:
