What's In A GIF

(main page)

These pages explain down to the bit level what's inside a GIF, and are offered in the hope they will be useful to programmers using GIFLIB.

The explanation is in three parts:

  1. Bits and Bytes - first we look at the file format that makes up a GIF file
  2. LZW Image Data - a closer look at how image data is compressed within a GIF file
  3. Transparency and Animation - how some of the more advanced features of GIF files work

Due credit: much of this material was written by one Mike Flickinger in 2005, though it has been significantly revised and expanded for GIFLIB. The illustrations are all his.

Back to GIFLIB documentation