@freebliss oh, that‘d be nice! I didn‘t find a solution, especially for the bad quality of the jpeg. But as I saw so many minor issues on their github, on which they were activly working, I thought this rather major one has to be me somehow. :)
I didn't yet look at the results in detail and side by side on a proper large monitor, but it seems there are possibly relevant quality differences, especially banding and artifacts in the skyline as you observed already.
If you want to try some other/your own images you can install rust from https://rustup.rs/ (super straight forward and quick, basically hit enter a few times :)), and inside the folder run "cargo run --release" to generate the tests. Code in "src/main.rs" should be simple to adapt (changing the image set, resolution, etc.) even without any rust knowledge. Let me know your findings, we can then move this forward to the developers in an issue.
@freebliss Made a pull request and added some comparisons. It seems to me that there‘s definitely a problem with higher quality settings. Higher frequency areas of the images seem ok though. Also noticed a green tint through all quality settings.
@claus super cool thanks, the closeup tiles and the large side by side comparison very clearly show what's going on. \o/ I'll open an issue with the crate maintainers in the next days then (or alternatively feel free to do it yourself of course). :)