Convert pnm to pfm Online: pnm2pfm

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

Go to Tom's Editor

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.

PFM

Portable Float Map is an image format with extension PFM.