Jamie is correct, image resizer looks at the width and height attributes of the image tag to determine the dimensions it should use, it will not work if you use CSS for these attributes.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.