Some links for taking the interactive component to the next level

Adding save image from canvas functionality:
http://www.nihilogic.dk/labs/canvas2image/
http://en.wikipedia.org/wiki/Data_URI_scheme

Getting URL parameters using JavaScript for passing data via a URL:
http://www.netlobo.com/url_query_string_javascript.html

Adding drag, drop and resize functionality to the canvas using the Kinetic.js library:
http://www.html5canvastutorials.com/labs/html5-canvas-drag-and-drop-resize-and-invert-images/