Portable Network Graphics (PNG) Specification (Third Edition) W3C Working Draft 20 July 2023

[parasew]

Not sure if there is an instant action item, but here is the W3C Working Draft of the PNG spec of 20 July 2023 (today).

Here are the changes since the 2nd edition of PNG:

• APNG has been added to the spec
• A new CICP chunk that paves the way for HDR support
• EXIF is part of the main spec

Wondering if oxipng would be covering APNG

[andrews05]

Nice, thanks for sharing.
Interesting to hear APNG is now official. Initial support for this was added to oxipng in #511.
cICP is also explicitly preserved by the safe strip option.
I don’t think anything needs to be done regarding EXIF.

[TPS]

Full APNG optimization support is being tracked in #551.

[andrews05]

Preliminary APNG support is now released.

[C0rn3j]

For people landing here and wanting to read more about the new PNG Third Edition just like I did:

• Changelog that OP linked¹ should be read from the linked page upwards for newer spec releases, reading downwards is just second edition changes and older, it's a bit confusing as the fragments do not contain their own date.
  • At the time of writing, spec repo has newer changelog² than the current website
• Spec repo has a nice Third Edition explainer³ document

Footnotes

1. https://www.w3.org/TR/png-3/#changes-20031110 ↩

2. https://github.com/w3c/PNG-spec/blob/main/index.html#L7547 - CTRL+F for F-ChangeList if line is out of date ↩

3. https://github.com/w3c/PNG-spec/blob/main/Third_Edition_Explainer.md ↩

[svgeesus]

The best link to keep up with changes to PNG third edition is
https://w3c.github.io/PNG-spec/#F-ChangeList

Glad the explainer is helpful!