I think there’s misunderstanding. Images are successfully added to the product, they’re also available in Media Library and when viewing product page, they’re also available there. But they’re not linked (attached) to the product in Media Library.
Thanks for the answer, but I don’t think this related to the issue. I’m creating the products using Woo API, all images are shown up in product page, but they’re not linked to the product in media library. I think this is my issue. Another issue is, I can’t rename the image filename when it’s uploading to the product via API. I’m not talking about the media name, but file URL (like productImage.png).