catalog\controller\product\product.php
исправить
if ($product_info['image']) {
$data['thumb'] = $this->model_tool_image->resize($product_info['image'], $this->config->get('theme_' . $this->config->get('config_theme') . '_image_thumb_width'), $this->config->get('theme_' . $this->config->get('config_theme') . '_image_thumb_height'));
} else {
$data['thumb'] = '';
}
на
if ($product_info['image']) {
$data['thumb'] = $this->model_tool_image->resize($product_info['image'], $this->config->get('theme_' . $this->config->get('config_theme') . '_image_thumb_width'), $this->config->get('theme_' . $this->config->get('config_theme') . '_image_thumb_height'));
} else {
$data['thumb'] = $this->model_tool_image->resize('placeholder.png', $this->config->get('theme_' . $this->config->get('config_theme') . '_image_thumb_width'), $this->config->get('theme_' . $this->config->get('config_theme') . '_image_thumb_height'));
}