The borrowed expression is a verb, yet its common feature is not simply one isolated property such as color or length. It rests on the configuration of several parts in a single scene.
The human posture relates knees, torso, and enclosing support; the horse-tack scene relates pommel, rein, and the hanging lines. The shared organization is the rhetorical point.
This elaboration helps explain why the image is unusual, but a composite resemblance is not automatically rare: some complex scenes may themselves be commonplace.