Zoom Image is an WordPress plugin that adds zooming effect over WooCommerce shops on featured images, thumbnails and variations in a simple and elegant mode.
Zoom Image offers a few options for customizing it to better suit your needs.
Customizing options can be found in your dashboard “Settings” -> “Zoom Image”.

Adding zoom effect over thumbnails: Tick the check box “Zoom over thumbnails”.
Changing zooming effect over featured image (effect style), “zoom effect style”: Select one from the two options /styles: “Window” ,”Inner”.

For better understanding on how Zoom Image works please check the “Screenshots” tab and the official page of the plugin: http://www.outsourcing-webdesign.com/wordpress-plugins/.