I think that the body proportions make them look like hobbit-pony centaurs! Look how round and stocky they are. Also, I'm intrigued that the centaur mare has a flat chest; presumably she has an udder beneath her hind end. This is an established, if uncommon, way of rendering female centaurs and allows them to be SFW even without clothes on.
Check out their coloration, too. The stallion is pretty clearly a chestnut. The mare could be either a grulla (images) (description) or a blue roan. Notice that her human hair matches the gray-brown tone of her horse hair.
I think it would be fun to see this picture developed a bit more, particularly their hooves.