同样的问题对我来说，我公开了文件，我能够以https://metapyxl.s3.amazonaws.com/images/1696425186798_1.png的身份访问我的图像
因此，您需要在S3 bucket上公开您的图像。
我附加的图像更新S3桶的权限。
Allow public access的
Allow Bucket policy的

require_once ABSPATH . 'wp-admin/includes/media.php';
require_once ABSPATH . 'wp-admin/includes/file.php';
require_once ABSPATH . 'wp-admin/includes/image.php';

function upload_image_from_url($image_url) {
    // Check if the URL is valid
    if (filter_var($image_url, FILTER_VALIDATE_URL)) {
        // Get the file type
        $file_type = wp_check_filetype(basename($image_url), null);

        // Prepare an array of data for the attachment
        $attachment = array(
            'post_title'     => sanitize_file_name(basename($image_url)),
            'post_mime_type' => $file_type['type'],
        );

        // Try to upload the image
        $attachment_id = media_sideload_image($image_url, 0, null, 'id');

        if (!is_wp_error($attachment_id)) {
            // The image was successfully uploaded, and $attachment_id contains the attachment ID.
            return $attachment_id;
        } else {
            // An error occurred during the upload.
            return false;
        }
    }

    return false;
}

// Example usage:
$image_url = 'https://metapyxl.s3.amazonaws.com/images/1696425186798_1.png';
$attachment_id = upload_image_from_url($image_url);

if ($attachment_id) {
    // The image was uploaded successfully. You can use $attachment_id as needed.
} else {
    // There was an error uploading the image.
}

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