How do I prevent all the images from my website from showing up in Google Search?

You want to add a "noindex" tag to every image, you can try this script that will should do that for you, add to header code injection:

  <script>
    // Get all image elements on the page
    const images = document.getElementsByTagName('img');

    // Loop through each image and add a meta tag with noindex to each one
    for (let i = 0; i < images.length; i++) {
      const image = images[i];

      // Create the meta tag
      const metaTag = document.createElement('meta');
      metaTag.setAttribute('name', 'robots');
      metaTag.setAttribute('content', 'noindex');

      // Append the meta tag to the image
      image.parentNode.insertBefore(metaTag, image);
    }
  </script>