A system and method permits design of customized items on a client device using a web page. The client device receives a web page from a web server that includes, among other things, a design document encoding graphic elements that completely characterize a design image. The client device receives edits to the graphic elements, and sends a modified design document back to the server. The server then uses the design document to render an image, and sends to the client the server-rendered image for display in the web page. The web page may define an area in which to display the server-rendered image. The server may use a database to store the rendered image and use it in completing a customer order.