How do I attach new images to a node? Will try to be brief.

I have a node with "n" images asigned to it, now i want to add new images (and keep the currents) to the node, i've  tried this but no success until now. The next code does nothing:

$node = Node::load($node_id);
$node-&gt;field_car_picture[] = $new_images;
$node-&gt;save();


Also tried this and removes the current pictures and leave only the new images:

$node = Node::load($node_id);
$node-&gt;field_car_picture-&gt;setValue($new_images);
$node-&gt;save();


Any help will be appreciated
You can try to merge the existing field items array and the new one, but I would use a loop to add one image at a time:

$node = Node::load($node_id);
foreach ($new_images as $new_image) {
  $node-&gt;field_car_picture[] = $new_image;
}
$node-&gt;save();


If you want to merge the arrays get the existing one

$existing_images = $node-&gt;field_car_picture-&gt;getValue();


combine it with the new array and replace the fields content with it.