diff --git a/modules/backend/formwidgets/FileUpload.php b/modules/backend/formwidgets/FileUpload.php
index 006ba8cfd..ad1395f29 100644
--- a/modules/backend/formwidgets/FileUpload.php
+++ b/modules/backend/formwidgets/FileUpload.php
@@ -212,7 +212,7 @@ class FileUpload extends FormWidgetBase
                 : 'width: '.$this->imageHeight.'px;';
 
             $cssDimensions .= ($this->imageHeight)
-                ? 'height: '.$this->imageHeight.'px;'
+                ? 'max-height: '.$this->imageHeight.'px;'
                 : 'height: auto;';
         }
         else {
@@ -221,7 +221,7 @@ class FileUpload extends FormWidgetBase
                 : 'width: auto;';
 
             $cssDimensions .= ($this->imageHeight)
-                ? 'height: '.$this->imageHeight.'px;'
+                ? 'max-height: '.$this->imageHeight.'px;'
                 : 'height: auto;';
         }