Convert png to pnm Online: png2pnm

You can use Tom's Editor to easily convert images from
Portable Network Graphics .PNG to Portable aNy Map .PNM.
Tom's Editor is a free, online image manipulation and converter program.

Go to Tom's Editor

PNG

Portable Network Graphics is an image format with extension PNG.

PNM

PNM images are uncompressed 24 bit RGB images. Can cannot store Alpha channel. PNM images come in 2 types: binary and text. Especially popular on Linux.