Convert hgb to pnm Online: hgb2pnm

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

Go to Tom's Editor

HGB

HinterGrundBild is an image format with extension HGB.

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.