Ugly ICO generated results

[nadrolinux]

Hello,
I created website for my wife's business few days ago and I found that images stored in *.ico generated file by RealFaviconGenerator looks really bad. I use the latest version of wordpress plugin, however standalone version works the same. You can check results with this image:
https://puciekgroomer.pl/wp-content/uploads/2024/11/puciek.png
I had to manually overwrite ico image generated with external tool inside wp-content/uploads/fbrfg and at now it looks fine:
https://puciekgroomer.pl/wp-content/uploads/fbrfg/favicon.ico

It looks like something is wrong with builtin ico generator.

Anyway thanks for this tool and have a nice day!
Patryk