I didn't know the PNG file format could receive updates, but it got one anyway

The humble PNG has been around for a while now, and it has done a lot of heavy lifting since its release. There are millions, if not billions, of images out there on the internet that use the lossless file format to keep things looking crisp, and it's my personal favorite file type when sharing images.

For the last two decades, PNGs haven't seen any changes. They've just sort of done their thing without complaint. That is, until today, when the W3C-owned Portable Network Graphics (PNG) Working Group released patch notes for a new kind of PNG file format, and honestly, I shouldn't be this happy over an update to an image file format.

The PNG file format gets an update after 20 years of stagnation

As spotted by Tom's Hardware, the head of the PNG Working Group, Chris Blume, made a post on his website describing what's going on with the PNG format. The main attraction is a tweak to how PNGs work to allow for proper HDR support. This means that images will now support richer colors and look better in general. It sounds like something that would really inflate how big a PNG image can get, but Chris Blume says that this addition only adds four bytes of data to the filesize. Chris also points to a post by one of PNG's co-authors that describes how all this works.

So, why PNG, and why now? Well, turns out, people really wanted PNGs that supported HDR:

The W3C Timed Text Working Group (think: subtitles) needed HDR support in PNG. A proposal was made, but a few experts decided we could do better. Momentum built, and additional parties became interested. Before we knew it, we had representation from (in alphabetical order) Adobe, Apple, BBC, Comcast / NBCUniversal, Google, MovieLabs, and of course W3C, who maintains the spec. It's quite the dream team.

Turns out that all of the main internet browser companies, including Chrome, Safari, and Firefox, already support HDR-based PNGs. No need to wait for an update, thank goodness.

While Chris was digging through the spec and seeing what needed updating, he decided that now would be a great time to bring up animated PNGs, or APNGs for short. Now the specification includes details on APNGs and how developers can use them. Chris claims that APNGs are "widely supported" today, but I haven't really seen them around; perhaps this update will fix that.

Chris finishes off by saying that there are two more updates planned. The next one (PNG fourth edition) will be "short" and will introduce "HDR & Standard Dynamic Range (SDR) interoperability." However, the fifth edition looks exciting, as it will introduce new methods of compression to help squash down the filesize. Here's hoping they won't take 20 years to come out.