magento2.2 – How to get the product image in magento2

I want to get the product image in magento2.

$ collection = $ this-> productCollectionFactory-> create ()
-> addStoreFilter ($ this -> _ storeManager-> getStore () -> getId ())
-> addAttributeToSelect (array (& # 39;))
-> addAttributeToFilter (
                    [
                        ['attribute' => 'name', 'like' => '%' . $searchQuery . '%'],

])
-> addFieldToFilter (& # 39; type_id & # 39 ;, ['eq' => "sellabletype"])

foreach ($ collection as $ product) {
$ image_url = $ this-> image-> init ($ product, & # 39; product_page_image_small & # 39;) -> setImageFile ($ product-> getSmallImage ()) -> resize (200, 200) -> getUrl ();
$ searchCollection[] = ['name' => $product->getName(), 'url' => $product->getProductUrl(), 'image' => $image_url];
}

But it only returns Magento_Catalog / images / product / placeholder / thumbnail.jpg url ….

How to get the URL of the product image

Thank you.