You can control the images sizes here - administrator/index.php?option=com_jshopping&controller=config&task=image. Make the Product image width and the Product thumbnail width the same and it should change the view you have.

You also need to add <define('_JSHOP_ZOOM_IMAGE', 'Zoom image');> (Change the second 'Zoom image' to your language) to your language file in root/components/com_jshopping/lang/ your language to get rid of the base code your picture shows.