Transactional emails are now database aware with regard to email logo image.

Author: Graham Wharton

app/code/Magento/Email/Model/AbstractTemplate.php

@@ -14,6 +14,7 @@
 use Magento\Store\Model\Information as StoreInformation;
 use Magento\Store\Model\ScopeInterface;
 use Magento\Store\Model\Store;
+use Magento\MediaStorage\Helper\File\Storage\Database;
 
 /**
  * Template model class
@@ -163,6 +164,11 @@ abstract class AbstractTemplate extends AbstractModel implements TemplateTypesIn
      */
     private $urlModel;
 
+    /**
+     * @var Database
+     */
+    private $fileStorageDatabase;
+
     /**
      * @param \Magento\Framework\Model\Context $context
      * @param \Magento\Framework\View\DesignInterface $design
@@ -177,6 +183,7 @@ abstract class AbstractTemplate extends AbstractModel implements TemplateTypesIn
      * @param \Magento\Framework\Filter\FilterManager $filterManager
      * @param \Magento\Framework\UrlInterface $urlModel
      * @param array $data
+     * @param Database $fileStorageDatabase
      *
      * @SuppressWarnings(PHPMD.ExcessiveParameterList)
      */
@@ -193,7 +200,8 @@ public function __construct(
         \Magento\Email\Model\TemplateFactory $templateFactory,
         \Magento\Framework\Filter\FilterManager $filterManager,
         \Magento\Framework\UrlInterface $urlModel,
-        array $data = []
+        array $data = [],
+        Database $fileStorageDatabase = null
     ) {
         $this->design = $design;
         $this->area = isset($data['area']) ? $data['area'] : null;
@@ -207,6 +215,7 @@ public function __construct(
         $this->templateFactory = $templateFactory;
         $this->filterManager = $filterManager;
         $this->urlModel = $urlModel;
+        $this->fileStorageDatabase = $fileStorageDatabase ?: \Magento\Framework\App\ObjectManager::getInstance()->get(Database::class);
         parent::__construct($context, $registry, null, null, $data);
     }
 
@@ -394,6 +403,11 @@ protected function getLogoUrl($store)
         if ($fileName) {
             $uploadDir = \Magento\Email\Model\Design\Backend\Logo::UPLOAD_DIR;
             $mediaDirectory = $this->filesystem->getDirectoryRead(DirectoryList::MEDIA);
+            if ($this->fileStorageDatabase->checkDbUsage() &&
+                !$mediaDirectory->isFile($uploadDir . '/' . $fileName)
+            ) {
+                $this->fileStorageDatabase->saveFileToFilesystem($uploadDir . '/' . $fileName);
+            }
             if ($mediaDirectory->isFile($uploadDir . '/' . $fileName)) {
                 return $this->storeManager->getStore()->getBaseUrl(
                     \Magento\Framework\UrlInterface::URL_TYPE_MEDIA