Convert rpgm to pnm Online: rpgm2pnm

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

Go to Tom's Editor

RPGM

Portable aNy Map is an image format with extension RPGM.

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.