Build a Website -- 2

Hi I currently have a site where we will be selling various pre designed items. We want to give the customer the option to design their own items if they don’t like our designs. They can put their own text ,images in a predesigned template. So how this works is you go to my site and see this item [login to view URL] You don’t like it and want create your own you would then click the link that would take you to the design site. There you would customize it to your liking and place text and or images then place an order in the shopping cart. The customization would then be saved to me on the back end in a jpeg format so I could edit and fulfill the order. Some sample sites that have some of what we need are below the are card sites but the concept is the same i sell quoted items [login to view URL] [login to view URL] I’m looking for the most cost effective solution and want only competent developers that have a proposal that lays out how you will design and deliver simply replying to this job with (I can do it) will be ignored thanks