Custom borders feature request (libretro)

[GBPlayer85]

I would like to customize the default border. MiSTer does this by adding a ".sgb" file with the custom border. It may be done the same way adding the file to the RetroArch system folder.

Thanks!

[GBPlayer88]

This new tool by marcrobledo can generate .sgb files from .png images.

https://www.marcrobledo.com/super-game-boy-border-converter/