Asvin Balloo has posted a tutorial that shows how to combine the YUI libraries with PHP to create a simple image cropper.
This post will show you how to build an AJAX crop image tool using the image cropper control from YUI library and PHP. The ImageCropper Control from the YUI library gives you an interactive interface for getting the dimensions to crop an image and using these dimensions in PHP, we can do some cropping.
The script takes in an upload, shows it in the browser for cropping and once altered, pushes the altered image back out as a download. Full code is included as well as a demo of the final result and a sample file to get you started.