Well, artificial leather is not actually leather. You just need to draw a little string from “artificial” to “fake”.

Have you tried just

cjxl test.png test.jxl -d 0 -e 9

instead of relying on third party websites?

It is part of libjxl which you should be able to get on on any modern Linux distribution or even on Windows without any issues.

It’s not even that, PNG to lossless JXL is actually stupidly efficient if we are speaking pure file size. Either the website is doing something wrong or it’s some weird edge case.

I’ve been using it for a while, haven’t noticed the candidate box margins being weird until you mentioned it.

You can make the font for the candidate box larger to fill the unoccupied space, but that sounds like a bad solution.

It’s developer opened an issue for improving that part of the keyboard not that long ago, probably there is something in the works. You may want to voice your concerns there.