PNG has been updated for the first time in 22 years — new spec supports HDR and animation
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It's great that Papua New Guinea is still receiving updates /s
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I hate that you can’t right click copy images, it always wants to share as a link. Plus some other issues when sharing, but it’s just such a pain in the ass.
That’d be the browser’s (or whatever app you’re using) fault, not the format. I guess you could choose to hate it for poor support.
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2029 Headline: Worlds largest data breach caused by zero day exploit in popular PNG 3.0 renderer
the payload was reportedly embedded in an animated image of the attacker repeatedly flicking his left testicle
That was because they added 'shorts' and friend-lists to it.
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Right, and it depends on what "quite off target" means. Are we talking about greens becoming purples? Or dark greens becoming bright greens? If the image is still mostly recognizable, just with poor saturation or contrast or whatever, I think it's acceptable for older software.
So it depends on the specific HDR encoding used, Rec2020 is the most common ones you'll see (It's meant for "pure" setups, i.e. where the source and output are tightly linked, e.g. gaming consoles or blu-ray, or so) and the raw data won't look great. While something like HLG (Hybrid-Log Gamma) is designed for better fallback (As it's meant for TV broadcast, where the output device is "whatever TV the user has"), so should just look dimmer.
This is a HDR screenshot I took of Destiny 2, which uses Rec2020, tone mapped to SDR
And here's the raw screenshot data from before tonemapping.
If the second image had all the right HDR metadata, and the viewer supported it properly, then both images would match.
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JXL can do lossy images (like JPEG) and lossless ones (like PNG), and on average it'll produce smaller file sizes than both (While beating JPEG quality wise). The killer feature is that it can do lossless recompression of existing JPEG files and shave off about 20% of the file size, and it's reversible so you can turn those JXL files back into JPEG images for existing software.
The downside is that it was created by Google Research (among others), but the Chrome team made AVIF instead and decided that's what they'd support and nothing else.
At least Safari supports it.
lossless recompression of existing JPEG
Uh… how does it make a JPEG lossless? Or is it lossless in that it makes a JXL out of a JPEG without affecting the original JPEG quality (i.e. no further loss beyond JPEG's)?Being able to turn JPEGs into JXLs and JXLs back to JPEGs is cool, though
What's with the AVIF thing? Yet another I am unfamiliar with (all I know about image formats is JPG = worse quality, PNG = better quality, GIF = animated (and something WebP. Idk much about that one either))
Also, in my research, I've found something about the distinction between lossless JXL vs lossy JXL. Seems like you wouldn't be able to tell if the image is lossy or lossless just from it being a JXL
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lossless recompression of existing JPEG
Uh… how does it make a JPEG lossless? Or is it lossless in that it makes a JXL out of a JPEG without affecting the original JPEG quality (i.e. no further loss beyond JPEG's)?Being able to turn JPEGs into JXLs and JXLs back to JPEGs is cool, though
What's with the AVIF thing? Yet another I am unfamiliar with (all I know about image formats is JPG = worse quality, PNG = better quality, GIF = animated (and something WebP. Idk much about that one either))
Also, in my research, I've found something about the distinction between lossless JXL vs lossy JXL. Seems like you wouldn't be able to tell if the image is lossy or lossless just from it being a JXL
WebP is the same, it's got a lossy mode (VP8) and a lossless mode (Which is more limited than PNG, but beats it where it overlaps). But to make it more complicated the lossless mode also has lossy processing modes, where it alters the image first to achieve smaller output sizes.
People have a long habit of turning JPEG files into PNG files, the file extension won't help you there. They also could have reduced the colour depth or resized it, all lossy operations. All it really tells you is that it can have an alpha channel.
As for AVIF, personally I don't like the format, it feels like an "open media" (But still patented) version of HEIF to oppose Apple. Like WebP it makes the (baseless IMO) assumption that a format designed to encode motion data is better at encoding still data than a format designed to encode still data. It's got all the limitations of a video format (It's got a max resolution, only supports 12bit images, and no progressive decoding), and they left out all the enhancements from WebP (The dedicated lossless mode, "lossless AVIF" files are huge and the last I checked badly supported, so nobody actually used them, and they just called very high quality settings "lossless")
A team inside of Google was working on WebP2 around the same time, that used AV1 but actually added the useful stuff like efficient lossless encoding, it got killed too in favour of AVIF.
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I hate that you can’t right click copy images, it always wants to share as a link. Plus some other issues when sharing, but it’s just such a pain in the ass.
To ELI5 this, this happens when whoever made the webpage put a text layer above the image - probably on purpose to make it harder for people to download the image.
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WebP is the same, it's got a lossy mode (VP8) and a lossless mode (Which is more limited than PNG, but beats it where it overlaps). But to make it more complicated the lossless mode also has lossy processing modes, where it alters the image first to achieve smaller output sizes.
People have a long habit of turning JPEG files into PNG files, the file extension won't help you there. They also could have reduced the colour depth or resized it, all lossy operations. All it really tells you is that it can have an alpha channel.
As for AVIF, personally I don't like the format, it feels like an "open media" (But still patented) version of HEIF to oppose Apple. Like WebP it makes the (baseless IMO) assumption that a format designed to encode motion data is better at encoding still data than a format designed to encode still data. It's got all the limitations of a video format (It's got a max resolution, only supports 12bit images, and no progressive decoding), and they left out all the enhancements from WebP (The dedicated lossless mode, "lossless AVIF" files are huge and the last I checked badly supported, so nobody actually used them, and they just called very high quality settings "lossless")
A team inside of Google was working on WebP2 around the same time, that used AV1 but actually added the useful stuff like efficient lossless encoding, it got killed too in favour of AVIF.
Ooh, Alpha channel. Forgot of that. That is a nice one. Love me some alpha channel.
So, what would you say is best? If someone wanted to save an image, which format would you recommend? I usually go with PNG. JPG if I want bad quality on purpose (drag quality slider to minimum for extra compression)
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Ooh, Alpha channel. Forgot of that. That is a nice one. Love me some alpha channel.
So, what would you say is best? If someone wanted to save an image, which format would you recommend? I usually go with PNG. JPG if I want bad quality on purpose (drag quality slider to minimum for extra compression)
PNG gets you the best compatibility and features, at the expense of file size. But I probably wouldn't use it for uploading photographs to the web of course.
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I'm probably gonna be massively downvoted for saying the forbidden word but I asked AI to do a summary with references of the forward and backward compatibility of PNG's new version:
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Based on recent search results, the new PNG specification (Third Edition) and its reference library (libpng) maintain strong backward compatibility while introducing modern features. Here's a detailed compatibility analysis:
1. Backward Compatibility (Viewing Old PNGs with New Lib)- Full Support: The new libpng (1.6.49+) and PNG Third Edition fully support legacy PNG files. Existing PNGs (conforming to the 2003/2004 spec) will render correctly without changes .
- Implementation Stability: Libpng's API evolution (e.g., hiding
png_struct/png_infointernals since 1.5.0) ensures older apps usingpng_get_*/png_set_*functions remain compatible. Direct struct access, deprecated since 1.4.x, may break in libpng 2.0.x (C99-only) . - Security Enhancements: Critical vulnerabilities (e.g., CVE-2019-7317 in
png_image_free()) were patched in libpng 1.6.37+, making the new lib safer for decoding old files .
️ 2. Forward Compatibility (Viewing New PNGs with Old Lib)- Basic Support: Older libpng versions (pre-1.6.37) can decode new PNGs if they avoid new features. Core chunks like
IHDRorIDATremain unchanged . - New Feature Limitations:
- HDR Imagery: Requires libpng 1.6.45+ and apps supporting the
mDCvchunk. Older libs ignore HDR data, falling back to SDR, which may cause color inaccuracies . - APNG Animation: Officially standardized in PNG Third Edition. Older libs (e.g., <1.6) treat APNG as static images, showing only the first frame .
- EXIF Metadata: New
eXIfchunks are ignored by legacy decoders, losing metadata like GPS or copyright info .
- HDR Imagery: Requires libpng 1.6.45+ and apps supporting the
- Security Risks: Older libs (e.g., ≤1.6.36) contain unpatched vulnerabilities (e.g., CVE-2015-8126). Parsing malicious new PNGs could exploit these flaws .
Compatibility SummaryScenario Compatibility Key Considerations Old PNG → New Lib 
ExcellentLegacy files work flawlessly; security improved. New PNG → Old Lib ️ PartialBasic rendering works, but HDR/APNG/EXIF ignored. Security risks in unpatched versions. New Features 
ConditionalRequires updated apps (e.g., Photoshop, browsers) and OS support . 3. Implementation and Industry Adoption- Broad Support: Major browsers (Chrome, Safari, Firefox), OSs (iOS, macOS), and tools (Photoshop, DaVinci Resolve) already support the new spec .
- Progressive Enhancement: New features like HDR use optional chunks, ensuring graceful degradation in older software .
- Future-Proofing: Work on PNG Fourth Edition (HDR/SDR interoperability) and Fifth Edition (better compression) is underway .
Conclusion- Upgrade Recommended: New libpng (1.6.49+) ensures security and full compatibility with legacy files.
- Test Workflows: Verify critical tools handle new features (e.g., APNG animation in browsers).
- Fallbacks for Old Systems: For environments stuck with outdated libs, convert new PNGs to legacy format (e.g., strip HDR/APNG) .
For developers: Use
png_get_valid(png_ptr, info_ptr, PNG_INFO_mDCv)to check HDR support and provide fallbacks .!<
I do not have downvotes on my instance, so please, have a
