Convert SLK to PNM

An SLK file, standing for Symbolic Link File, is a specialized file type used primarily in spreadsheet applications to facilitate data exchange. Originally introduced by Microsoft for its Multiplan spreadsheet program in the 1980s, the SLK format was later adopted by other spreadsheet software due to its simplicity and efficiency. These files are composed of ASCII text and include symbolic references to cells, allowing for easy parsing and manipulation of spreadsheet data. The primary use of SLK files is to enable seamless data transfer between different spreadsheet programs, ensuring compatibility and preserving the integrity of the data during exchange.

The PNM (Portable Anymap) file extension, developed by Jef Poskanzer in the 1980s, stands for Portable Any Map. It is an uncompressed raster graphics format designed for portable image storage and exchange, encompassing three sub-formats: PBM (Portable Bitmap), PGM (Portable Graymap), and PPM (Portable Pixmap). PNM files store image data in plain text or binary format, ensuring easy usage across different platforms and applications. This format is widely supported by various image editing software and is valued for its simplicity and lossless compression.