pnmtopng(1) on Linux
The text 8f9fde3b809e, as Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy), Debian 6.0 (Squeeze), Debian 5.0 (Lenny), Debian 4.0 (Etch), Debian 3.1 (Sarge), Debian 3.0 (Woody) shipped it.
convert a portable anymap into a Portable Network Graphics file
Flags it lists
-
-alpha -
-background -
-compression -
-downscale -
-filter -
-force -
-gamma -
-hist -
-interlace -
-text -
-transparent -
-verbose -
-ztxt