Add PNG (Third Edition, 2023) to "More info"

[svgeesus]

The currently maintained W3C PNG specification is the Third Edition:

https://w3c.github.io/PNG-spec/

This incorporates the APNG chunks, and also adds several new chunks related to High Dynamic Range (HDR) images

Changes

[nayuki]

This is feedback regarding the project's web page https://www.nayuki.io/page/png-library .

I am aware of this W3C document but am hesitant to link to it because it says "Editor's Draft" and I fear that sections of it or the whole document could be invalidated.

[svgeesus]

Fair point, and it has been published, here
https://www.w3.org/TR/png-3/

but that link is only updated every few months (there will be an update soon). The Editor's Draft is the up to date consensus of the working group.

Either way, the Third Edition has important corrections compared to the old 2003 Second Edition.

[svgeesus]

A heads up, PNG became a Candidate Standard 21 Sept 2023. Implementations of the new features are encouraged.