PNG

APNG Edit
A firefox extension to allow the creation and editing of APNG files.
https://addons.mozilla.org/firefox/addon/5519

APNG Specification
An extension of the PNG image format, adding support for animated images. Includes full specification including file structure and version changes.
http://wiki.mozilla.org/APNG_Specification

PNG
Information, applications, and code relating to the PNG image format.
http://www.libpng.org/pub/png/

PNG Resources of the Miscellaneous Persuasion
Links to images, mailing lists, test images, PNG and image compression documents, comics and websites using PNGs, the official site, and some unofficial resource sites.
http://www.libpng.org/pub/png/pngmisc.html

PNG Tips for Cartoonists
Article written to encourage cartoonists to use PNG and to share tips on exploiting PNG's strengths.
http://hackles.org/etc/png.html

PNG-Tech
A collection of comments, impressions, comparisons, experiments and ideas regarding the PNG (Portable Network Graphics) file format, and related technologies: ZLIB (Data Compression Format and Library), and MNG (Multiple-Image Network Graphics). It is focused on the compression algorithms used in PNG.
http://www.cs.toronto.edu/~cosmin/pngtech/

Portable Network Graphics - PNG
Thorough introduction to PNG image format.
http://www.mywebsite.force9.co.uk/png/

The Sad Story of PNG Gamma Correction
Explains how PNG gamma "correction" causes color mismatches with other colors on web pages.
http://hsivonen.iki.fi/png-gamma/

W3C: PNG
W3C overview of PNG. Includes browser tests to see if gamma and alpha work correctly.
http://www.w3.org/Graphics/PNG

Open Source Graphics with PNG
Joe Barr discusses PNG, the new open source file format, and the Unisys/CompuServe/GIF controversy. [LinuxWorld] <small>(September 9, 1999)</small>
http://www.linuxtoday.com/news_story.php3?ltsn=1999-09-09-021-04-PS

The Story of PNG
An article detailing the history of the PNG format. <small>(February 29, 1999)</small>
http://www.libpng.org/pub/png/slashpng-1999.html