[IDEA] IMG Thumbnail support

Hi,
i want to create a plugin but i don't mnow how to start.
I can work good with PHP and JS, but i dont know how to create a plugin for FCKEditor.

There has to be an extra tab on the insert image tool, naed Thumbnail.
You choose an image and with this jquery plugin: http://joanpiedra.com/jquery/thumbs/ there will be created a thumb.
And there will automatically be added an Lightbox to the full-sized image on the thumbnail.

I cant find how to create that with an extra tab and how to insert that thumbnail in the editor.

I thought this idea out in my head, but don't know how to do it in FCKEditor.
Can anybody help me to get a start on this?

When I finished it i will put the plugin here on the forums, becuase I think it will be a really useful plugin that a lot of people need right now, but doesn't exist.

I hope u understand, thanks!