Add an event called "update" to the sprite system,  which fires each time the image changes.
This can improve performance because the bitmap is only being drawn when needed, and other code can use this event to only update when needed.

Most sprites don't tend to animate at 30 FPS anyway.
Just make sure to "update" when the pose, charset, and direction change... and also initially.

It might also be a good idea to fire a "change" event after the sprite system displays its initial frame of animation.