Convert OPML to PNM

OPML, or Outline Processor Markup Language, is a file format utilized primarily for outlining data structures. Initially developed in 2000 by UserLand Software, OPML was designed to facilitate the exchange of outline-based information between different software applications. Its uses have expanded over time, notably in organizing RSS feed lists and managing hierarchical data. The OPML file extension denotes XML-based documents that offer simplicity and interoperability in transferring structured information across diverse platforms. In essence, OPML serves as a versatile tool in the realm of data organization and syndication.

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.