Last modified: Sat Feb 9 14:56:00 UTC+0100 2019 © A. Tarpai
The first PNG image under investigation
About
PNG is well-documented and patent-free (http://www.libpng.org).
It lossless compresses true-color, grayscale and palette-based images of 1,2,4,8 and 16 bit depths of packed pixel formats.
Compression is based on encoding differences from neighbour pixel data (filters) and using the DEFLATE algorithm.