This is a format created in the Acorn Draw program, intended for image visualization by using vector lines. It’s used for storing information in the publishing business (brochures, logotypes, etc.). The main advantage is it’s high quality source images when printing. It’s been in use since 1980.
This format was used to store bitmap and vector images natively on Macintosh computers. It was used for laying out and sharing images between programs. It used JPEG compression algorithms and RLE encoding. Today, the PICT format is used in the Windows environment with the PCT extension.