Convert PJPEG to G3

The PJPEG (Progressive JPEG) is a file extension for images that enhances the standard JPEG format by displaying images in successive waves of increasing detail, improving the user experience during slow network conditions. The JPEG stands for "Joint Photographic Experts Group", the organization that developed the standard in 1992. PJPEG is particularly useful for web applications, as it allows images to appear more quickly and progressively refine in quality, rather than loading from top to bottom like baseline JPEGs.

The G3 file extension refers to the CCITT Group 3 Fax Image, a standardized format developed by the Consultative Committee for International Telegraphy and Telephony (CCITT), now known as ITU-T. This format was created to efficiently compress black-and-white fax documents for transmission over telephone lines. It employs a method called Modified Huffman Coding for data compression, enabling reduced transmission time and bandwidth usage. G3 was widely adopted in the 1980s and 1990s as the primary standard for fax transmissions, ensuring compatibility across different fax machines and systems.