Hello @Shehzad Ghazi,
The product images have been rendered by WooCommerce, so you will need to go to Appearance > Customize > WooCommerce > Product Images > Main Image width > set 800, Cropped (1:1) and regenerate thumbnails using the plugin. After that, please clear your browser cache and check back to your site.
We also recommend that you read this article for further information: https://xstore.helpscoutdocs.com/article/89-product-images
Best Regards,
8Theme’s Team