Url instead of Woocommerce thumbnail

Question

I have several thousand photos to add as "thumbnail". The products are already added to WooCommerce, but without the "thumnail". What do I have:

• links to photos that are related to the SKU
• each product has a special "photo" attribute that displays a link to the photo. How do I transfer all this to a thumbnail automatically?

I want to change the default "thumbnail" to download from url. It works on FRONT, but I get an error in the admin when I go to the products tab "Call the get_attribute () member function on null"

function alterImageSRC($image, $attachment_id, $size, $icon){      
    
    global $product;
    $koostis = $product->get_attribute( 'pa_featured-images' );  
   
    $image[0] = "https://link.com/wp-content/uploads/thumbs/'$koostis'";

    return $image;
}
add_filter('wp_get_attachment_image_src', 'alterImageSRC', 10, 4);

Answer 1

I did it. I'm attaching a working code that generates a thumbnail based on an attribute. There is a link to the picture in the atrubucie of this product.

function alterImageSRC($image, $attachment_id, $size, $icon){      
    $product = wc_get_product();
    $optimex_featured = $product->get_attribute( 'pa_featured-images' );
    $image[0] = "https://link.com/wp-content/uploads/thumbs/'$optimex_featured'";
    return $image;
}
add_filter('wp_get_attachment_image_src', 'alterImageSRC', 10, 4);