Player customized skins

How could I go about implementing a system to allow players to upload their own character skin and have the client use the skin for their character and see other player’s skins in an online game? From what I have heard I would use asset bundles but I have no idea if that would work or not.

@shinytwig

I know this is an old post, but did you find a solution?
I am currently working on a RPG where the player can customize every texture. (like Minecraft)