Convert ist to pnm Online: ist2pnm

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

Go to Tom's Editor

IST

Interlace Studio is an image format with extension IST.

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.