Catalog image dimensions is a woocommerce feature. If you are experiencing wrong dimensions for hover images , you will need to set the correct dimension for catalog images at products/display under woocommerce/settings menu.
After changing it you may need to regenerate product thumbnails using this plugin.
If you still getting same dimensions on shop page check media settings page configuration. For example - if you are getting 150*150 dimension on hover images and media settings page has 150 * 150 thumbnail size. try changing it and regenerating thumbnails using aforementioned plugin.