Removing Slack From Image Files?

After searching for a while for a topic/software that would do this, I got nothing.

Say I have “Game” from 1998 (No Protections). When I burn it, the image is always 700MB, yet the files in the CD only add up to like 25 MB. I was wondering how you could create a working bootable image using the previous 1:1 (or close) image of the game and then some program to cut off the extra space within the ISO/MDS/NRG/etc.

Btw I’m using Alcohol 120% v1.9.5 (3105), and Daemon Tools v4.00

Found UltraISO. Works like a charm.

UltraISO is a fantastic program. 2nd that suggestion.