Convert csv to pnm Online: csv2pnm
You can use Tom's Editor to easily convert images from
.CSV to Portable aNy Map .PNM.
Tom's Editor is a free, online image manipulation and converter program.
Go to Tom's Editor
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.
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.