Install grub-splashimages by entering the following commands in the terminal:
sudo apt update sudo apt install grub-splashimages
Description:
a collection of great GRUB splashimages
This package contains a collection of splashimages which can be used for GRUB. If you'd like your splashimage in this package send them as bug report to Debian BTS.
Homepage: http://ruslug.rutgers.edu/~mcgrof/grub-images/
Version: 1.2.3
Section: universe/admin