Magento 2 Get all product images in on product list page

In magento 2.3.4 i get this like this. You can get all images of the product by gallery ReadHandler

 <?php
    namespace VendorModuleControllerIndex;
    
    class DownloadPictures extends MagentoFrameworkAppActionAction
    {
        protected $_pageFactory;
    
        public function __construct(
            MagentoFrameworkAppActionContext $context,
            MagentoFrameworkViewResultPageFactory $pageFactory,
            MagentoCatalogApiProductRepositoryInterfaceFactory $productRepositoryFactory,
            MagentoCatalogModelProductGalleryReadHandler  $GalleryReadHandler
        )
        {
            $this->_pageFactory = $pageFactory;
            $this->_productRepositoryFactory = $productRepositoryFactory;
            $this->galleryReadHandler = $GalleryReadHandler;
            return parent::__construct($context);
        }
    
        public function execute()
        {
            $product = $this->_productRepositoryFactory->create()->getById($product_id);

            $galleryReadHandler = $this->galleryReadHandler->execute($product);
            $images = $galleryReadHandler->getMediaGalleryImages();
            foreach ($images as $image) {
               print_r($image->getUrl());
            }
    
        }
    }

Hope this helps give upvote if it helps

There is a function available in magento MagentoCatalogModelResourceModelProductCollection::addMediaGalleryData() which will add media gallery images to your product collection.

Just use it on your collection like,

$collection->addMediaGalleryData();

And you will be able to get media gallery images using

$_product->getMediaGalleryImages()

$product->getMediaGalleryImages()->getItems()

returns an array with the gallery images

foreach ($product->getMediaGalleryImages() as $_image) {
      $array[] = $_image->getFile();
}
echo $array;

create helper for example :

<?php
/**
 * Copyright © 2015 Magento. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace IbnabCommonHelper;
use MagentoCatalogModelProductGalleryReadHandler as GalleryReadHandler;
class Data extends MagentoFrameworkAppHelperAbstractHelper {
  protected $galleryReadHandler;
    /**
     * Catalog Image Helper
     *
     * @var MagentoCatalogHelperImage
     */
    protected $imageHelper;
    public function __construct(
    GalleryReadHandler $galleryReadHandler,  MagentoFrameworkAppHelperContext $context,MagentoCatalogHelperImage $imageHelper)
    {
        $this->imageHelper = $imageHelper;
        $this->galleryReadHandler = $galleryReadHandler;
        parent::__construct($context);
    }
   /** Add image gallery to $product */
    public function addGallery($product) {
        $this->galleryReadHandler->execute($product);
    }
    public function getGalleryImages(MagentoCatalogApiDataProductInterface $product)
    {
        $images = $product->getMediaGalleryImages();
        if ($images instanceof MagentoFrameworkDataCollection) {
            foreach ($images as $image) {
                /** @var $image MagentoCatalogModelProductImage */
                $image->setData(
                    'small_image_url',
                    $this->imageHelper->init($product, 'product_page_image_small')
                        ->setImageFile($image->getFile())
                        ->getUrl()
                );
                $image->setData(
                    'medium_image_url',
                    $this->imageHelper->init($product, 'product_page_image_medium')
                        ->constrainOnly(true)->keepAspectRatio(true)->keepFrame(false)
                        ->setImageFile($image->getFile())
                        ->getUrl()
                );
                $image->setData(
                    'large_image_url',
                    $this->imageHelper->init($product, 'product_page_image_large')
                        ->constrainOnly(true)->keepAspectRatio(true)->keepFrame(false)
                        ->setImageFile($image->getFile())
                        ->getUrl()
                );
            }
        }
        return $images;
    }
}

call and use inside your list.phtml : $_helperGallery = $this->helper('IbnabCommonHelperData'); now you can use with current called product inside for each (with you technique):

  <a href="<?php echo $_product->getProductUrl() ?>">
                            <ul class="product-item-wrapper">
                                <?php
                                $_helperGallery->addGallery($_product);
                                $images = $_helperGallery->getGalleryImages($_product);
                                if ($images instanceof MagentoFrameworkDataCollection) {
                                    $i = 1;
                                    foreach ($images as $image) {
                                        $item = $image->getData();
                                        if (isset($item['media_type']) && $item['media_type'] == 'image'):
                                            ?>
                                            <?php if ($i == 1): ?>
                                                <li class="selected">
                                                <?php else: ?>
                                                <li >
                                                <?php endif; ?>
                                                <img src="<?php echo isset($item['medium_image_url']) ? $item['medium_image_url'] : null; ?>" alt="Preview image">
                                            </li>
                                            <?php
                                            $i++;
                                        endif;
                                    }
                                }
                                ?>
                            </ul>
                        </a>

the complete source of course

Category loading has changed in 2.1, so this may only be relevant from 2.1 onwards:

The image gallery is added to the product via an extension interface defined via di.xml. The upshot is that we can manually create an instance of the gallery ReadHandler class and pass a product to load all its gallery images.

As usual in Magento 2 the best way to instantiate a class is via the __construct() method, so here is a stub block class:

use MagentoCatalogModelProductGalleryReadHandler as GalleryReadHandler;

class Gallery
{
    protected $galleryReadHandler;

    public function __construct(
        GalleryReadHandler $galleryReadHandler
    )
    {
        $this->galleryReadHandler = $galleryReadHandler;
    }

    /** Add image gallery to $product */
    public function addGallery($product)
    {
        $this->galleryReadHandler->execute($product);
    }
}

In your template, assuming you have $product loaded via a product collection, you would be able to call:

$block->addGallery($product);
$images = $product->getMediaGalleryImages();
foreach ($images as $image) {
    ...
}

Use below code to get all gallery images on product list page:

<?php
    $objectManager = MagentoFrameworkAppObjectManager::getInstance();
    $product = $objectManager->create('MagentoCatalogModelProduct')->load($_product->getId());        
    $images = $product->getMediaGalleryImages();
    foreach($images as $child){ ?>
        <img src="<?php echo $child->getUrl(); ?>" >
<?php } ?>

You can use the exact same method as Magento 1:

$_product->getMediaGallery('images')

Also, Magento 2 provides a new method to get the media gallery as an array:

$_product->getMediaGalleryEntries():