Convert pnm to csv Online: pnm2csv
You can use Tom's Editor to easily convert images from
Portable aNy Map .PNM to Comma-Separated Value
Tom's Editor is a free, online image manipulation and converter program.
Go to Tom's Editor
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.
CSV are simple text files used mainly to store tables (as in Microsoft Excel). Saving images as CSV means converting to grayscale and storing every pixel in a different cell of a table.