Use GIMP, or some other program in which you can Multiply layers. Go to your Texture folder, and find the c-textures of f-textures {feline or canine}. Just pull these up in your program, copy it, then open up your preset-picture {body, tail, head, etc} and paste it, then send to new layer. Finally, multiply both layers and it will come up textured. Merge them together and save, and you have your textured preset!