Very sexy and playful girl you have there! If she is sending you fun photos then you know there is a desire and a will to be more risque.
Keep encouraging her to be a little more daring in the photos she takes when you are apart, and maybe go shopping together to get her some clothes that can easily let others see more of her sexy body... Wrap skirts, dresses and tops all can be demure and yet have great sexy fun exposure potential, as do skirts with high slits in front which reveal great lengths of thigh with each step, and the sides often separate when a woman is seated. Add in some thigh high stockings and high heel shoes / boots for a great ensemble. Sheer tops are always fun though not always practical in the winter.
Good luck and keep posting updates!!