Well, I don't quite understand the logic compared to previous code but I think I finally got it.
public function displayAjax() { $combinationId = (int)Tools::getValue('product_attribute_id'); $product = new Product((new Combination($combinationId))->id_product); $images = $product->getCombinationImages($this->context->language->id); $selectedCombinationImages = $images[$combinationId]; die(Tools::jsonEncode(array($images))); }
I do not know if it's the cleanest optimized way but it works.
I have one more thing to figure out though I think as Tools::jsonEncode() appears to be deprecated.