most of the time PSX games fit onto a 650 meg cdr! if your image is over that then put a 700meg cdr in your writer and burn! it should go on if your writer can handle overburn. most cdr can handle an overburn of about 10megs but it all depends on your writer.

what programme r u using to burn?
try flashing the rom on ur writer so it can handle overburn if it kicks the cdr out before its finished. if u need more help just ask i was a newbie once so i know wot it was like