diff --git a/src/Umbraco.Web/PublishedCache/XmlPublishedCache/PublishedMediaCache.cs b/src/Umbraco.Web/PublishedCache/XmlPublishedCache/PublishedMediaCache.cs
index 32130fe1e8..93e55a3705 100644
--- a/src/Umbraco.Web/PublishedCache/XmlPublishedCache/PublishedMediaCache.cs
+++ b/src/Umbraco.Web/PublishedCache/XmlPublishedCache/PublishedMediaCache.cs
@@ -540,8 +540,8 @@ namespace Umbraco.Web.PublishedCache.XmlPublishedCache
                     {
                         // use property type to ensure proper conversion
                         var propertyType = _contentType.GetPropertyType(i.Key);
-                        
-                        if (i.Key != "isDoc" && i.Key != "image")
+
+                        if (propertyType != null) 
                             property = new XmlPublishedProperty(propertyType, false, i.Value); // false :: never preview a media
                     }