Overlay images on product templates

I need a script developed for a PHP website i'm working on. The website allows anyone submit a design to be placed on different products such as iPhone cases, samsung cases, t-shirts e.t.c It would involve overlaying an image on top of a blank product template and saving the final product. An example of what i want to achieve is here: [login to view URL] My guess is this involves overlaying the design using css or javascript while positioning the other features of the case (e.g. camera) and then saving the product using javascript or php. I'm not sure of this so any suggestions would be great. Ex: For an iPhone case, the camera and other features (side buttons) would still need to show. Take into consideration the curved edges as well.