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Comment by carra | Hacker News Reader

Thanks, but just like WEBP I'll try to stick to regular JPEGs whenever possible. Not all programs I use accept these formats, and for a common user JPEG + PNG should mostly cover all needs. Maybe add GIF to the list for simple animations, while more complex ones can be videos instead of images.

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You can really treat WebP as a universally available format in 2026. It is an old, boring, and safe format to use now.

Browser support for WebP is excellent now. The last browser to add it was Safari 14 in September 16, 2020: https://caniuse.com/webp

It got into Windows 10 1809 in October 2018. Into MacOS Big Sur in November 2020.

Wikipedia has a great list of popular software that supports it: https://en.wikipedia.org/wiki/WebP#Graphics_software

Webp can be really annoying once you hit certain encoding edge cases.

One customer of mine (fashion) has over 700k images in their DAM, and about 0.5% cannot be converted to webp at all using libwebp. They can without problem be converted to jpeg, png, and avif.

Just out of curiosity, what's the problem libwebp has with them? I wasn't aware of cases where any image format would just cross its arms and refuse point blank like that.

Webp has a maximum pixel dimension size of 16383 x 16383.[0]

[0] https://developers.google.com/speed/webp/faq#what_is_the_max...

We have never been able to resolve it better than knowing this:

Certain pixel colour combinations in the source image appear to trip the algorithm to such a degree that the encoder will only produce a black image.

We know this because we have been able to encode the images by (in pure frustration) manually brute forcing moving a black square across the source image on different locations and then trying to encode again. Suddenly it will work.

Images are pretty much always exported from Adobe, often smaller than 3000x3000 pixels. Images from the same camera, same size, same photo session, same export batch will work and then suddenly one out of a few hundred may become black, and only the webp one not other formats, the rest of the photos will work for all formats.

A more mathematically inclined colleague tried to have a look at the implementation once, but was unable to figure it out because they could apparently not find a good written spec on how the encoder is supposed to work.

Have you reported this bug? It sounds interesting what the authors would say.

No. Our experience with reporting issues in Skia and other such Google libraries has left a bitter impression, so we simply avoid it.

Can you try converting one of them here? I'm curious whether it works or not.

https://bulkresizephotos.com/en?preset=true&scale=100&format...

If it doesn't work, any chance I could have a copy of one of the images for testing with? (and trying to file the right bugs to get it fixed)

Unfortunately being universal implies way more than just having good browser support. There are quite a few image processing programs without webp or jpeg-xl support. I'm using Windows 11 and the default image viewer can't even open webp... Also, keep in mind that due to subscription models there are many people stuck with older Photoshop versions too.

You just need this: https://apps.microsoft.com/detail/9pg2dk419drg

Thanks, I know about this and other workarounds. My point is, if it was truly universal you should not need anything! I bet most regular users will never even know this exists.

I never knew about this either and it's been very frustrating as I've been converting my Manga library over to webp (savings are insane) and doing any spot checking opens Edge.

Edit: After reading the comments, this doesn't seem to open in Photos App.

"JPEG XL" is a little bit of a misnomer as it's not just "JPEG with more bits". It supports lossless encoding of existing content at a smaller file size than PNG and allows you to transcode existing JPEGs recoverably for a 20% space savings, the lossy encoding doesn't look nearly as ugly and artifacted as JPEG, it supports wide gamut and HDR, and delivers images progressively so you get a decent preview with as little as 15% of the image loaded with no additional client-side effort (from https://jpegxl.info/).

It is at least a very good transcoding target for the web, but it genuinely replaces many other formats in a way where the original source file can more or less be regenerated.

Honestly, I don't like how webp and now jpegxl support both a lossless and lossy mode.

Let's say you want to store images lossless. This means you won't tolerate loss of data. Which means you don't want to risk it by using a codec that will compress the image lossy if you forget to enable a setting.

With PNG there is no way to accidentally make it lossy, which feels a lot safer for cases you want lossless compression.

Taking a look at the reference codec package at https://gitlab.com/wg1/jpeg-xl, they note:

> Specifically for JPEG files, the default cjxl behavior is to apply lossless recompression and the default djxl behavior is to reconstruct the original JPEG file (when the extension of the output file is .jpg).

You're right, however, that you do need to be careful and use the reference codec package for this, as tools like ImageMagick create loss during the decoding of the JPEG into pixels (https://github.com/ImageMagick/ImageMagick/discussions/6046) and ImageMagick sets quality to 92 by default. But perhaps that's something we can change.

You can use too few bits of color depth to get lossyness in PNG. More generally, I can't find myself very sympathetic to "I don't want a format that can do X and Y, because I might accidentally select X when I want Y in my software". You might accidentally choose JPG when you want PNG too. Or accidentally resample the image. Or delete your files.

If you want a robust lossless workflow, PNG isn't the answer. Automating the fiddly parts and validating that the automation does what you want is the answer.

PNG can and is often used in a lossy way. Reducing the number of colors so PNG8 can be used instead of PNG24/PNG32 is the most common way to do that. Tools like pngquant exist, and for example Photoshop when exporting to PNG also has an option to reduce the colors, to flatten the image (remove alpha), or to change the colorspace.

16-bit PNG files can easily accidentally be reduced to 8-bit, which is of course a lossy operation. Animated PNG files can easily get converted into a still image (keeping only the first frame). CMYK images will have to be converted to RGB when saving them as PNG, which is also a lossy operation. It can happen that an image gets created as or converted to JPEG and then gets saved as PNG - which of course is a bad and lossy workflow, but it does happen.

So I don't agree that with PNG there is no way to accidentally make it lossy.

In any case: lossless or lossy is not a property of a format, but of a workflow. For keeping track of provenance information and workflow history, I would recommend looking into JPEG Trust / C2PA, which is a way to embed as metadata what happened to an image since it was captured/generated. Relying on the choice of image format for this is fragile and doesn't allow expressing the nuances, since reality is more complicated than just a binary "lossless or lossy".

You should never use GIF anymore, it is super inefficient. Just do video, it is 5x to 10x more efficient.

https://web.dev/articles/replace-gifs-with-videos

There's odd cases where it still has uses. When I was a teacher, some of the gamifying tools don't allow video embeds without a subscription, but I wanted to make some "what 3D operation is shown here" questions with various tools in Blender. GIF sizes were pretty comparable to video with largely static, less-than-a-second loops, and likely had slightly higher quality with care used to reduce color palette usage.

But I fully realize, there are vanishingly few cases with similar constraints.

For those you can often use animated WebP, or even APNG. They all have close to universal support and are usually much smaller.

AVIF works here also. Discord started supporting it for custom emoji.

If you need animated images in emails or text messages, GIF is the only supported format that will play the animation. Because of the size restrictions for these messaging systems the inefficient compression of GIFs is a major issue.

I am not sure "need" is the right word here.

only if looping information is stored inside the container.

Videos and images are treated very differently by browsers and OS:es. I'm guessing the better suggestion would be to use apng or animated avif if you are looking for a proper gif alternative.

Do browsers support progressive enhancement from gif to animated avif without javascript? The royally messed that up for animated webp.

Yes, by using the <picture> element with <source> elements declaring the individual formats with the last one being a regular <img> with the gif.

Or you could use content-negotiation to only send avif when it's supported, but IMO the HTML way with <picture> is perhaps clearer for the client and end user.

I think the webp problem was due to browsers supporting webp but not supporting animation, transparency or other features, so content negotiation based on mime types (either via <picture> or HTTP content-negotiation) did not work properly. Safari 16.1-16.3 has the same problem with AVIF, but that is a smaller problem than it was with webp.

So I guess that's a no - avif support does not necessarily mean animated avif support.

I covered this in my comment:

> Safari 16.1-16.3 has the same problem with AVIF, but that is a smaller problem than it was with webp.

Unfortunately browser vendors didn't want to support silent looping videos in <img> tags so gif stays relevant.

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