ISOLINUX.CFG

Hopefully someone out there with a far better knowledge of Linux than me
can answer the following I am in the process of building a recovery DVD
for remote users, I have done the basics as in written a shell script for
the correct driver sets etc to install and modified the menu system no
problem. However I would like to be able to change the splash screen in
the ISOLINUX.CFG there is a line which reads gfxboot bootlogo.

So first question is what type of file is it and can a different one be
put in and what sort of format does it need to be?

Second question is are there any variables on these and if so what are
they, and what do they do?

vga=0x0314 splash=silent mode=2 CDBOOT=YES showpts
vga=0x0314 splash=silent mode=5 CDBOOT-YES showpts

Thank you for any help

--
Phil