I have continued to make refinements to GRUB Customizer. Installing a Menu Background Image seems to be a real problem in RH distros including CentOS. Some people have been successful; others not. Since my previous post
viewtopic.php?f=47&t=65532
I have continued my experimentations. I noted in my last post that whatever image you chose you had to first *had* to convert it to a 640x480 px (Step 2). This is NOT true. Whatever image you choose should match that of your monitor or smaller. 640x480 px seems to be a universal size, and is more geared towards a laptop rather than a workstation. In my case that would be 1920x1080. If you pick a more detailed image shrink it to the resolution of your monitor.
In Step 3 I stated that the image *had* to be set to a 14 color palette. This too is NOT true. Modify Step 3 to read: Goto --> Image --> Mode --> LEAVE AS RGB --> Select CONVERT TO COLOR PROFILE
Skip Step 4
The file still needs to be exported as in Step 5 and saved as a .png file. Pay particular attention to Steps 6-10
When you start GRUB Customizer and you choose the Font for your Menu make sure to select one that is a Sans Mono font otherwise the menu text will look horrible. Size is preferential but Size 14-20 looks best and BOLD makes it readable .
Finally it pays to check your /etc/default/grub file. It should look like this. Here is mine:
GRUB_TIMEOUT="5"
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT="saved"
GRUB_DISABLE_SUBMENU="true"
#GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="crashkernel=auto rhgb quiet nouveau.modeset=0 rd.driver.blacklist=nouveau"
GRUB_DISABLE_RECOVERY="true"
export GRUB_COLOR_NORMAL="white/black"
export GRUB_COLOR_HIGHLIGHT="light-green/black"
GRUB_BACKGROUND="/boot/grub/73264-wallpaper1.png"
#GRUB_GFXMODE="saved"
GRUB_SAVEDEFAULT="true"
GRUB_FONT="/boot/grub2/unicode.pf2"
Check your handiwork, save, and reboot your machine. With luck you will see your menu on your spiffy background.
Enjoy!!!