Hacking how do i shrink iso's

[mop999]

in the backup launcher it says in the FAQ

"""""Q. Why is Super Smash Bros. Brawl is not working?
A. Dual layer DVDs are not supported in this release. You need to shrink it.""""

how can i shrink a iso

 

[tj_cool]

http://gbatemp.net/index.php?showtopic=78029