PICtor is an image file format developed by John Bridges, the principal author of PCPaint, the first Paintbrush program for the PC.
It was also the native file format for Pictor Paint and Graphics Animation System for Professionals (GRASP) (also by Bridges) and became the first widely accepted DOS imaging standard.
[1] The PICtor format is a device-independent raster image format; the file header stores information about the display hardware (screen resolution, color depth and palette information, bit planes, and so on) separately from the actual image information, allowing the image to be properly transferred and displayed on computer systems with different hardware.
The encoding of a PIC file is also optimized for decoding quickly onto the native device that it was created on.
As the file is processed during decoding, the child blocks in each parent block are unpacked either into an off-screen buffer if not displaying in native mode, or directly into the display adapter if in native mode (which results in quicker unpacking).