Multi image upload cannot be done in this way.
An image upload behavior must be created for each file field on the page.
Image upload is not supported with the multi insert behavior. It would require a fair bit of hand coding to accomplish.
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.