Jon Sneyers

LGTM modulo some typos/nitpicks.

> There is no default CMS implementation in some cases and I am very much against introduction behaviour that works in some cases but not others :) What are the...

LGTM as it is now, I wanted to approve but I cannot do that since I started this PR :)

> Should this be merged, @jonsneyers? Yes please :)

[OpacityFunNoMerged.psd.zip](https://github.com/ImageMagick/ImageMagick/files/2648173/OpacityFunNoMerged.psd.zip)  Here is a test image which has some layers but no merged image. The PNG file is what it should look like (this is what you get if...

If you want all efforts to make the same quality-affecting choices, then that leaves only room for differences in the entropy coding, not all the other encoder heuristics. I don't...

For lossless compression, I think it's reasonable to have this expectation, and while we don't currently have this guarantee, if you find a counterexample we will treat it as a...

It's the latter. We're working on it. See also https://github.com/libjxl/libjxl/pull/2632 16000x16000 is 256 megapixels, which is 768 megabytes when using 8-bit RGB buffers, but libjxl uses 32-bit buffers so it's...

Hard to predict. Might be no or little difference, could be a huge difference if you're currently using disk swap space.

Is there any error message it gives? Anyway, a 3.3 gigapixel image will require too much memory to process with the current encoder, except maybe if you do `cjxl -e...