Having a 32G UFD used to boot a 700MB Debian install is not really the most efficient thing to do and flashing a new iso every time you want to change install image neither. This page is here to solve this problem by tutoring how do install and use Multisystem which is a software allowing you to boot from multiple image installed on one UFD.
Website of the project: http://liveusb.info/dotclear
gksu installl-depot-multiboot.sh |