Convert qrt to pnm Online: qrt2pnm
You can use Tom's Editor to easily convert images from
DKB Trace / Qrt raytrace .QRT to Portable aNy Map .PNM.
Tom's Editor is a free, online image manipulation and converter program.
Go to Tom's Editor
QRT
DKB Trace / Qrt raytrace is an image format with extension QRT.
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.