Convert pdf to pnm Online: pdf2pnm

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

Go to Tom's Editor

PDF

Adobe PDF format is the most popular document format. Overcomplicated. Offers compression.

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.