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. 


https://wordpress.org/plugins/regenerate-thumbnails/



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.