Hi there,
the Zoom image uses the original full size image you uploaded. So simplest way is to upload smaller images. Or you can add this PHP snippet:
add_filter( 'woocommerce_single_product_zoom_options', 'custom_single_product_zoom_options', 10, 3 );
function custom_single_product_zoom_options( $zoom_options ) {
// Changing the magnification level:
$zoom_options['magnify'] = 0.7;
return $zoom_options;
}
https://docs.generatepress.com/article/adding-php/
Just adjust the $zoom_options['magnify'] = 0.7;
size