I don't know what you mean by splitting bones and images.
The effect can be accomplished by setting the a bone's scaleX to -1. They animate some "turn" movement, flip the character with -1 scaleX, then animate the rest of the "turn" movement. Beware disabling inherit scale will prevent an ascendant bone's scale from affecting a descendant bone.
At runtime you often want the code to control which direction the character is facing. You'd animate everything facing right, then flip the skeleton to face left using Skeleton scaleX -1, which is not affected by disable inherit scale. If you use disable inherit scale, you could use events to have runtime code do the correct flipping.