The Royal is the style we built first, and the one most people send as gifts. It works because the joke isn't on your pet. There's no aren't we silly, no cartoon crown sitting at the wrong angle. The painting is rendered in the register of the court portraits in the National Gallery, with the kind of crimson velvet, ermine trim and soft window light that Reynolds would have used on the Duchess of Devonshire.
It pairs naturally with the rooms that already lean classical — panelled studies, formal dining rooms, hallways with antique furniture — but it also reads beautifully in a modern flat as the one piece of ironic-sincere art on the wall. The trick is that it's not ironic. The pet is genuinely treated as a sitter.
A Royal works best on pets with character in the face: the slight side-eye, the resting expression that already looks like judgement. Tortoiseshells, French bulldogs, sphynx cats, beagles, Persians. If your pet has been described as imperious, this is the style.
