Download files from array of links, create File entities and attach them to node

$files = [];
$index = 1;
foreach ($pictures as $picture) {
 $filename = 'image_' . $offer_id . '_' . $index . '.jpg';
 $destination = 'sites/default/files/product-photos/' . $filename;
 $response = \Drupal::httpClient()->get($picture, ['sink' => $destination]);
 if ($response->getStatusCode() == '200') {
   $file = File::create([
     'uri' => 'public://product-photos/' . $filename,
     'status' => 1,
     'uid' => 1,
   ]);
   $file->save();
   $files[] = [
     'target_id' => $file->id(),
     'alt' => $filename,
     'title' => $filename,
   ];
 }
 $index++;
}
$node->set('field_photo', $files);
$node->save();