Hello,
Please read this article https://docs.woocommerce.com/document/fixing-blurry-product-images/ To change the size of the product images go to WooCommerce > Settings > Product > Display > Image settings + don’t forget to regenerate thumbnails after changes (use Regenerate thumbnails plugin).
Zoom effect shows the real size of images, if you don’t want the zoom you can disable it in Theme Options > E-commerce > Single Product Page.
Regards