Custom Product Configurator Using Javascript/PHP

Question

I know this is a pretty broad questions but for learning purposes I'm trying to create a site similar to https://knockaround.com/shop/sunglasses/custom/custom-premium. I'm having trouble finding tutorials on how to accomplish this. I'm sure I can create the dropdowns to switch the images for the product, but where would I start when trying to pass the merged image to the cart? Also, I'm pretty sure the website uses Magento and Prototype JS. If someone could get me started in the right direction that would be great.

Thanks

Solution

Like this framework (http://fancyproductdesigner.com/), it must be merging the images on the server and created a single image saved with the cart entry.