how to convert image to sprite code like this for mario fullscreen

Question

i downloaded this game mario fullscreen https://codeload.github.com/karol-f/FullScreenMario/zip/refs/heads/master and i want to change characters and the of characters is like this, how i can convert an image to this, there is a parser.html in this code but it doesn't works.

this code is in library.js

p[0,6,8,10]x05,x25,x07,11x27,1100111131311313x16,3313113133x15,33311113331100x35,113333x05,331333313x06,33x16,3x05,222211112220003332233332233003333223322333003333212212333003333x26,333000333x26,3300

the game is this :

the parser is this . it don't give me sprite code