diff --git a/src/AssetControlExtension.php b/src/AssetControlExtension.php
index 32e77890..ac1a7790 100644
--- a/src/AssetControlExtension.php
+++ b/src/AssetControlExtension.php
@@ -247,7 +247,7 @@ protected function findAssets(DataObject $record)
             }
 
             // Omit variant and merge with set
-            $next = $record->dbObject($field)->getValue();
+            $next = $record->dbObject($field)?->getValue();
             unset($next['Variant']);
             if ($next) {
                 $files[] = $next;
diff --git a/src/File.php b/src/File.php
index b2a19c88..04e8da45 100644
--- a/src/File.php
+++ b/src/File.php
@@ -1322,16 +1322,14 @@ public function forTemplate(): string
 
     /**
      * Return a html5 tag of the appropriate for this file (normally img or a)
-     *
-     * @return string
      */
-    public function getTag()
+    public function getTag(): string
     {
         $template = $this->File->getFrontendTemplate();
         if (empty($template)) {
             return '';
         }
-        return (string)$this->renderWith($template);
+        return $this->renderWith($template);
     }
 
     /**
diff --git a/src/Shortcodes/FileShortcodeProvider.php b/src/Shortcodes/FileShortcodeProvider.php
index bc7d165c..2a9bcd27 100644
--- a/src/Shortcodes/FileShortcodeProvider.php
+++ b/src/Shortcodes/FileShortcodeProvider.php
@@ -18,8 +18,9 @@
 use SilverStripe\View\HTML;
 use SilverStripe\View\Parsers\ShortcodeHandler;
 use SilverStripe\View\Parsers\ShortcodeParser;
+use SilverStripe\View\SSTemplateEngine;
 use SilverStripe\View\SSViewer;
-use SilverStripe\View\SSViewer_FromString;
+use SilverStripe\View\ViewLayerData;
 
 /**
  * Provides shortcodes for File dataobject
@@ -237,9 +238,9 @@ protected static function find_error_record($errorCode)
      */
     public static function getCacheKey($params, $content = null)
     {
-        $key = SSViewer::config()->get('global_key');
-        $viewer = new SSViewer_FromString($key);
-        $globalKey = md5($viewer->process(ArrayData::create([])) ?? '');
+        $key = SSTemplateEngine::config()->get('global_key');
+        $engine = SSTemplateEngine::create();
+        $globalKey = md5($engine->renderString($key, ViewLayerData::create([])));
         $argsKey = md5(serialize($params)) . '#' . md5(serialize($content));
 
         return "{$globalKey}#{$argsKey}";
diff --git a/tests/php/ImageManipulationTest.php b/tests/php/ImageManipulationTest.php
index 5e815f0a..22111d45 100644
--- a/tests/php/ImageManipulationTest.php
+++ b/tests/php/ImageManipulationTest.php
@@ -22,8 +22,9 @@
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Core\Injector\Injector;
 use SilverStripe\Dev\SapphireTest;
-use SilverStripe\View\SSViewer;
 use PHPUnit\Framework\Attributes\DataProvider;
+use SilverStripe\View\SSTemplateEngine;
+use SilverStripe\View\ViewLayerData;
 
 /**
  * ImageTest is abstract and should be overridden with manipulator-specific subtests
@@ -447,10 +448,10 @@ public function testRender(string $template, string $expected)
     {
         /** @var Image $origin */
         $image = $this->objFromFixture(Image::class, 'imageWithTitle');
-
+        $engine = new SSTemplateEngine();
         $this->assertEquals(
             $expected,
-            trim($image->renderWith(SSViewer::fromString($template)) ?? '')
+            trim($engine->renderString($template, ViewLayerData::create($image)))
         );
     }