Background image when starting "the feather"

[clunga]

First of all thanks for answering at that time of the day. Let's get to the point. I had already managed in the lite 386 to change the image in the theme etc, BUT it works only for 1 second  during the process the pc is turned down. I had the same in Ubuntu, the background pops out only when shutting down. My change approach was to rename the image  I had chosen , xxyy.png to  background.png and with thunar file manager  paste it in the themes directory, substituting the original.
Following the bootin config, I have also changed the grub_linux_lite.png, but I am not surprised it does not show, as I am in dual boot and in this way, the splash image of linux mint leading the booting appers.
BUT, BUT, here lies the matter, I see during the booting, at a certain point a yellow image or screen with the logo on top. I will change the logo and tell you what happens, putting a ps on this post.
Thanks again
PS Sorry, it does not change, even if I changed the logo. If it were possible to go through the script,  I am specifically referring to the windows which appears after the black windows when all the operations are enumerated in smal whte chracters, and before the login page with the password. There in this lapse of time ( 7 or 8 seconds, this screen appears. Total screen, very similar to /usr/share/plymouth/themes/liteboot/1background.png, then it evens lights up furtherly and then is replaced by the login scree, with the password.
Thanks again.
PS2 I am not interested in the desktop back ground as I have variety which overrules them