Animated Textures

So I've got someone doing the wolf animated eyes and tail because I could learn but there willing to do it and It'd look bad however. They want me to see if animated mob textures work by adding an animated state with red spots on it that are super obvious problem is, I've never animated a texture. I'd want to use blockbench probably as I don't have paint.net or adobe photoshop, so could anyone help?
Thanks