The difference between a web developer and a web designer, is that a web designer is like a interior decorator, and the web developer is like the general contractor or builder. True a general contractor can probably help you make some aesthetic decisions, but for best results you always include a interior designer or decorator when building a home. The opposite is also true: an interior decorator can possibly have some building skills, but you would never hire one to build your home. The skill sets are related, but not the same. Similarly, a web designer can possibly build your website (but generally not very well) and your web developer can probably design your site (but generally not very well). For best results, a website is first designed, and then the developer breathes life into the designs, bringing them to life.