diff --git a/libraries/classes/Controllers/TransformationWrapperController.php b/libraries/classes/Controllers/TransformationWrapperController.php
index e2c5e11e23..acf92db0c1 100644
--- a/libraries/classes/Controllers/TransformationWrapperController.php
+++ b/libraries/classes/Controllers/TransformationWrapperController.php
@@ -24,6 +24,7 @@ use function imagesx;
 use function imagesy;
 use function in_array;
 use function intval;
+use function round;
 use function str_replace;
 use function stripos;
 use function substr;
@@ -167,10 +168,10 @@ class TransformationWrapperController extends AbstractController
                 . ($mime_options['charset'] ?? '');
         }
 
-        Core::downloadHeader($cn, $mime_type);
+        Core::downloadHeader($cn ?? '', $mime_type ?? '');
 
         if (! isset($_REQUEST['resize'])) {
-            if (stripos($mime_type, 'html') === false) {
+            if (stripos($mime_type ?? '', 'html') === false) {
                 echo $row[$transform_key];
             } else {
                 echo htmlspecialchars($row[$transform_key]);
@@ -194,11 +195,11 @@ class TransformationWrapperController extends AbstractController
             $ratioHeight = $srcHeight / $_REQUEST['newHeight'];
 
             if ($ratioWidth < $ratioHeight) {
-                $destWidth = $srcWidth / $ratioHeight;
-                $destHeight = $_REQUEST['newHeight'];
+                $destWidth = intval(round($srcWidth / $ratioHeight));
+                $destHeight = intval($_REQUEST['newHeight']);
             } else {
-                $destWidth = $_REQUEST['newWidth'];
-                $destHeight = $srcHeight / $ratioWidth;
+                $destWidth = intval($_REQUEST['newWidth']);
+                $destHeight = intval(round($srcHeight / $ratioWidth));
             }
 
             if ($_REQUEST['resize']) {