OpenCart 2.0 Module/Extension

We are a printing company trying to extend our services, we come up with creating a new website for creating/printing wallpapers for houses. We used OpenCart V2.0 as an eCommerce system to suite our needs and we are in about 75% off finishing it. The problem is, we are having difficulty with a specific feature that we really need to progress on. The scenario is, we offer customers to select any images in our categories and they will have to input their wall size first(height x width) and after that we would like to have an overlay box over the image depending on what size they input for HxW to re-position/scale the image for the wall size. If you didn't get my explanation, please visit [login to view URL] and go play around with the steps. We would like to have a very similar feature like that if possible. If you have any more questions/suggestions please contact me.