This package contains a collection of splashimages which can be
used for GRUB2. The splashimages are located in
/usr/share/backgrounds/grub. To change the background
edit the /etc/default/grub file and add this line
GRUB_BACKGROUND="/usr/share/images/grub/SOME_IMAGE.png"
after saving the file run grub-mkconfig -o /boot/grub/grub.cfg

Note:
Do not enable both GRUB_THEME and GRUB_BACKGROUND at the
same time.