Convert rfg to pnm Online: rfg2pnm

You can use Tom's Editor to easily convert images from
LEGO Mindstorms EV3 Robot Graphics File .RFG to Portable aNy Map .PNM.
Tom's Editor is a free, online image manipulation and converter program.

Go to Tom's Editor

RFG

LEGO Mindstorms EV3 Robot Graphics File is an image format with extension RFG.

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.