Custom Skin Packs are locked

When I created a custom skin pack for myself to use so that I don't have to save the texture to my desktop since I like to use lots of different skins. I have everything correct as I could find low resources to check, If this is not already a feature in the game, then I feel like this sure definitely be a a feature. If a user, like my self, like using multiple skin then why should we not be able to swap between the skin we choose