Convert a PPM image to an ASCII image using ANSI terminal color codes. See also:
ppmtoterm
,pbmtoascii
,pbmto4425
. More information: https://netpbm.sourceforge.net/doc/ppmtoascii.html.
ppmtoascii path/to/input.ppm > path/to/output.txt
ppmtoascii -2x4 path/to/input.ppm > path/to/output.txt