How to open an explorer window for user to upload content into the game?

The title pretty much says it. I’m building a game where the user can upload pictures (possibly video) into the unity game. I’m just wondering what code can be used to accomplish this? The game would be designed to run on iOS and Android if that makes a difference.

I would imagine after the upload it would be just a matter of assigning that uploaded file to an empty texture file or something like that in game right?

-Kaze-

Easiest method would probably be with the WWW functions, like -