Sounds like you're trying to split the sorter images, I don't think limezu made those for splitting they're just as directory to find where is what. The actual images are all individual already in their respective folders, however the generic ones don't have a folder of their own so they're scattered about the other folders, which is a nightmare to find something specific I ended up hacking out the one I wanted from the sorter. I used gamemaker's tool to do that and just messed with the settings until it was accurate.
Maybe try just cropping the rest of the image out and make sure the sprite you want is accurately positioned in a 64 x 96 png
I really hope he makes a separate folder for the generic ones it takes so much time trying to find any because they're not named and you don't know where they are :(