Develop a module for Website

I have a website and need you to develop a module that will provide the following feature. I sell swimming pool water slides and want to be able to show the client what their swimming pool area would look like if it had a water slide. Need a web program in which the client can upload a photo of their swimming pool and select any of our water slides (stored in a drop down menu) and bring it into the photo. The client can then view real time image of their swimming pool with different water slides. A problem that needs to be solved is the scale of the pool photo and the scale of the slide will be different and would need correction.(In other words a photo taken from a distance will make the pool look smaller and the water slide will look out of proportion)