Hello @rojr55,
The feature yo adjust the product image size is available within the plugin itself.
Just go to WooCommerce > Settings > Products > Display, be sure that the maximum image sizes are at least as big as the dimensions your theme is rendering for those thumbnails. Then Save Changes.
Also after this do not forget to regenerate your thumbnail using the plugin given below:
https://wordpress.org/plugins/regenerate-thumbnails/
Also, we really appreciate your interest in the premium version of the theme. If you want to know more about the pro version please refer to below link:
http://themepalace.com/downloads/easy-commerce-pro/
Thank you.
If you have any query further, please let us know.
Best Regards!!