The product image zoom module helps your main image box looks great with jQuery zoom. The user can mouse-over the image and the larger image view of that particular area shows up on the screen next to the main image (user can magnify a specific part of the image without having to open the images in a new window). Also, all images under "More Views" load on the product page itsef and make use of the localized zoom function of the extension. Installation will take approximately 5 minutes.

If you want to this module works with the additional images, you will need have to change the zen cart code so that when users click any additional image, the main image will replace with that additional image and when you hover it, the zoom will be apply.