That can only be because the browser isn't finding the images where it expects them to be. First, have you uploaded the images to your site? If you have, look at the code of the page to see what the links to the images look like. They might be pointing to your own hard drive. If they are, you need to make sure that your site has been properly defined in Dreamweaver, and then re-export the images to your site's assets or images folder. Save the page in Dreamweaver before uploading it to your site.