If you are using your local machine you might have the appData folder on your actual laptop but using a shared database. You are sure those files are uploaded to the server and not just locally on your machine?
So to clear things out, are you trying to centralize the media for your development team so everybody can use the same content for development? Maybe you can put the upload folder under source control to share it with the team?
I am working with EPiServers built in MediaData. I want to be able to drag and drop documents into the media folder in EPiServer and then use them on my website. My problem is that when I am upploading files from my local folder I am the only one that can open does files. The only thing that I have done so far is creating a class that inherits from Mediadata. Do I have to do something more?