Web services/server advice

Hi all, first post.

So the game I'm making is to be for the android and ios. The game involves having customisable characters but the number of textures for combinations could be quite high so it makes sense not to bundle them with the application(as there is a size limit anyway).

So what I want to do is download textures from a web service I set up, easy enough using a www object. The thing is in order to determine which texture to download I first want to send info to a database which will respond with which textures are available according to the info passed in.

I'm not very experienced with server stuff but I know its best not to access a database directly so instead there should be a middle man like a script that sits on the web service that accesses the database or something. This is the part I know nothing about. If I am supposed to use a script how do I pass it parameters and receive data like which texture to download(or even have the script pass back the texture itself). Also if the game does miraculously make it big are scripts even the right way to go about handling a large load?

Any help much appreciated.