Changing Grub Background/Color

I'm having trouble changing the Grub settings. I tried Grub Customizer, and was able to change the default boot (Bodhi, of course), but no luck with the background stuff. So I tried changing the color, or adding a picture, using the terminal. No luck there either. Also tried using the file manager (Thunar), same result. I can open the etc/default/grub.cfg file, but when I look at the entries there, there is nothing re: colors (00,00,00 etc). The picture I tried was listed, but it won't open it. (It is 8 bit, 256 color, RGB so that's not the problem).

Is there something in Bodhi that is preventing me from making these changes?