I like the idea of you atop Bay while Frodo stands in front of a supply-laden Fatty (you hold the reins to avoid an awful trampling incident!). Be sure he is up front, so that it looks like he is defending you from something!
Be sure to wear a cloak and the Evenstar and be sure he is wearing the Ring!
Oh my.... That is a hard photo to set up! - Not just one animal that doesn't know the word "stay" but two!