The way to do this, using Magento best practices is:
1. Create a new module and in your module.xml add
<!-- Ensures this module runs after Magento_Sales module is loaded by Di -->
<sequence>
<module name="Magento_Sales" />
</sequence>
2. create a Vendor/Module/view/adminhtml/layout/sales_order_view.xml file with the below
<?xml version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<referenceBlock name="order_items">
<arguments>
<argument name="columns" xsi:type="array">
<!-- This is for your new column heading in <thead> -->
<item name="image" xsi:type="string" translate="true">Product Image</item>
<item name="product" xsi:type="string" translate="true">Product</item>
<item name="status" xsi:type="string" translate="true">Item Status</item>
<item name="price-original" xsi:type="string" translate="true">Original Price</item>
<item name="price" xsi:type="string" translate="true">Price</item>
<item name="ordered-qty" xsi:type="string" translate="true">Qty</item>
<item name="subtotal" xsi:type="string" translate="true">Subtotal</item>
<item name="tax-amount" xsi:type="string" translate="true">Tax Amount</item>
<item name="tax-percent" xsi:type="string" translate="true">Tax Percent</item>
<item name="discont" xsi:type="string" translate="true">Discount Amount</item>
<item name="total" xsi:type="string" translate="true">Row Total</item>
</argument>
</arguments>
<referenceBlock name="default_order_items_renderer">
<arguments>
<argument name="columns" xsi:type="array">
<!-- This is for your new column data in <tbody> -->
<item name="image" xsi:type="string" translate="false">col-image</item>
<item name="product" xsi:type="string" translate="false">col-product</item>
<item name="status" xsi:type="string" translate="false">col-status</item>
<item name="price-original" xsi:type="string" translate="false">col-price-original</item>
<item name="price" xsi:type="string" translate="false">col-price</item>
<item name="qty" xsi:type="string" translate="false">col-ordered-qty</item>
<item name="subtotal" xsi:type="string" translate="false">col-subtotal</item>
<item name="tax-amount" xsi:type="string" translate="false">col-tax-amount</item>
<item name="tax-percent" xsi:type="string" translate="false">col-tax-percent</item>
<item name="discont" xsi:type="string" translate="false">col-discont</item>
<item name="total" xsi:type="string" translate="false">col-total</item>
</argument>
</arguments>
</referenceBlock>
</referenceBlock>
</body>
</page>3. Create an etc/di.xml file with the following to override the DefaultRenderer block for the item columns.
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
<type name="Magento\Sales\Block\Adminhtml\Order\View\Items\Renderer\DefaultRenderer">
<plugin name="order-view-image" type="Vendor\Module\Plugin\DefaultRendererPlugin" sortOrder="1" />
</type>
</config>4. Create your plugin at Vendor/Module/Plugin/DefaultRendererPlugin.php with the following contents
<?php
namespace Vendor\Module\Plugin;
use \Magento\Catalog\Helper\Image as ImageHelper;
class DefaultRendererPlugin {
/**
* @var \Magento\Catalog\Helper\Image $imageHelper
*/
protected $imageHelper;
/**
* @param ImageHelper $imageHelper
*/
public function __construct
(
ImageHelper $imageHelper
)
{
$this->imageHelper = $imageHelper;
}
public function aroundGetColumnHtml(\Magento\Sales\Block\Adminhtml\Order\View\Items\Renderer\DefaultRenderer $defaultRenderer, \Closure $proceed,\Magento\Framework\DataObject $item, $column, $field=null) {
// $column will equal the name value from sales_order_view.xml that was added
if($column === 'image') {
$img = $this->imageHelper->init($item->getProduct(), 'small_image')->setImageFile($item->getProduct()->getImage())->resize(200)->getUrl();
$result = '<img src="'.$img.'" alt="'.$item->getName().'" />';
}
else {
if($field) {
$result = $proceed($item,$column,$field);
}
else {
$result = $proceed($item,$column);
}
}
return $result;
}
} 5. Recompile (Showing full compilation just in case all is needed)
bin/magento module:enable vendor/module
bin/magento setup:upgrade
bin/magento s:d:c
bin/magento s:s:d -f
N.B Please never edit core files e.g. in vendor/ always override them and never use the objectManager, always make proper use of the dependency injection system
