Convert PGM to SIX

The Portable Graymap (PGM) file extension, originating in the late 1980s as part of the Netpbm project, stands for "Portable Gray Map". It serves as a simple, versatile format for grayscale images, enabling easy reading and writing by various programs. Due to its straightforward structure and plain text encoding, it's often used in academic and research settings where ease of parsing and accessibility are crucial. PGM files store grayscale images in a compact, efficient manner, making them an essential tool for image processing tasks.

The SIX file extension, short for "six pixels", is a bitmap graphics format developed by Digital Equipment Corporation (DEC) for their terminals and printers. Introduced initially to send bitmap graphics to DEC dot matrix printers like the LA50, SIX later facilitated the transfer of soft fonts to terminals such as the VT220. This format encodes images using a series of six-pixel-high patterns, making it efficient for transmitting graphics over 7-bit serial links. Rediscovered around 2010, SIX remains in use with modern terminal emulators for tasks like video playback.