Sorry, I assumed you... Anyway. For example, Tearless on the forum has alt texture for canines and felines, (as do a number of other members, like Delay). These files can be used by adding a layer of say, the canine head to your preset layer and multplying the added layer. This will create a texture for your preset.
I apologize if that doesn't make sense, it's somewhat common knowledge with photo-editing programs. I'd also bet there's already a member made tutorial for this, if you would go look.
EDIT: you can also use the default textures that come with the game, the others are just more varied and look better in most cases.