Image slider with small backend?

I'm making an image slider, but the user has to be able to insert new slider and add text to every slide..

This doesn't seem easy because when you submit the script has to know if it has to update an existing photo, or the text, or insert a new one..

Any ideas? or pre-existing plugins that can do that?
Thanks!

This does not sound like a PHP question. Image sliders are on the client side and PHP is on the server side. This sounds more like a JQuery application. Please post the PHP code you have so far to do this.