You need to add the code as follows in your child theme’s functions.php file,save and run it. You can find the reference on what to add here: https://www.styledthemes.com/forums/topic/disable-zoom-on-single-product-woocommerce/.
It will disable your woocommerce gallery functions.
Then set up the product image size inside woocommerce > setting > products > display according to your image and and regenerate the thumbnail by using Regenerate Thumbnails plugin.
Hopefully it works!