User blog comment:PlasmoidThunder/The Handy-Dandy, Fancy-Dancy Super Animation Ripping Tutorial!/@comment-11619185-20140904191618/@comment-24796436-20140904192033

He does state that "this isn't a mandatory method that you have to use; both methods are fine, though this one is preferred." So, it's not a big deal if you don't have it.

However, I do wonder if this is possible with the GIMP freeware/software.