a module for adding Tags (like flickr tags) on every picture of gallery

Hi, I'm a newbie here in Gallery2, please bare with me. But i'd really want to try to create a gallery2 module but I don't know where to start.

I'd like to create a module for adding tags on every picture upload. Where they can add, edit, delete tags once the picture has been uploaded.

please someone guide me on where to start and how to create a module for this kind of stuff.

Or is there already a code for this but i just can't find it.

regards,

--reynan