Hello,
Basically, the product images are controlled by Woocommerce and our theme doesn’t influence this. WooCommerce Allows some settings that you can find under Appearance >> Customize >> WooCommerce >> Product Images.
Screenshot for Clarification: https://ibb.co/301pXzw
In your case, it seems that you have set the image width from crop to 300x300px.
Please try increasing the thumbnail width and then clear cache and check back.
Regards.
Xtemos Studios.