Convert bw to pnm Online: bw2pnm

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

Go to Tom's Editor

BW

Silicon Graphics RGB is an image format with extension BW.

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.