Adding an Image to the Boot Loader Screen

1. Open the /etc/default/grub file as root.
2. Edit the following configuration variables in the file:

   GRUB_TERMINAL=gfxterm
   GRUB_BACKGROUND=path_to_the_image.png

   Supported formats are PNG, JPG, JPEG, and TGA.
3. Create a new configuration file with a background image:

   grub2-mkconfig -o /boot/grub2/grub.cfg