fuif VS lepton

But they didn't even explain what FUIF or PIK might be in that section or even the entire article!

To understand that article required me searching for FUIF [1], PIK [2] and a brief explanation of what JPEG XL is trying to achieve.

I double down on my "complaint" - I'd call it constructive criticism - that article was poorly written. It's actually quite a good story that their Free Universal Image Format (FUIF) has achieved what it has. That's a great acronym, especially for a world that thinks JPEG XL is a good acronym! Why not put in in the article.

To save anyone else time:

[1] https://github.com/cloudinary/fuif

here is FUIF (one of JXL parents) author writing about benefits of progressive: https://github.com/cloudinary/fuif

There was also an update to it called FUIF - Free Universal Image Format

https://github.com/cloudinary/fuif

But it too got superseded by JPEG XL (.jxl) https://jpegxl.info/

JPEG XL can losslessy transcode JPEG into a smaller format. JPEG2000 (or WebP or anything but Lepton[0]) didn't offer that. Besides, we have gif and png for approximately the same space. gif still isn't gone. Displacement isn't necessary for a new format to become useful.

[0] https://github.com/dropbox/lepton

We also use https://github.com/dropbox/lepton to save disk storage. It give 20% saving in our experience.

It may not be directly related to your question, but Dropbox has developed a great open source software called Lepton. It is able to compress JPEGs losslessly and saves on average about 22% of storage space. The files are not readable after compression without decompression, but since your focus seems to be on archiving anyway, it might be handy. And for larger collections of high-resolution images, it can actually save a decent amount of storage space.

Just wondering, is there a "lossless" conversion from PNG/JPEG/etc to AVIF? Kinda like Lepton[1] but just re-compressing without further loss of details.

[1] https://github.com/dropbox/lepton