How exactly does this thing work? Is it inferring that you can somehow access the graphic sets (animation sets) of games within MAME?

"What Is RipaRoo?
RipaRoo is a tool that will rearrange mame character sets into there respective on screen sizes. Which is handy if you are porting a game to another platform, this means you no longer have to sit there for hours capturing screenshots.
"

http://www.geocities.com/pharg0ne/

Can anyone explain this a bit better?