diff --git a/media/interfaces.py b/media/interfaces.py
index 10fb246..0edc337 100644
--- a/media/interfaces.py
+++ b/media/interfaces.py
@@ -23,12 +23,19 @@ $Id$
 """
 
 from zope.interface import Interface, Attribute
+from zope.i18nmessageid import MessageFactory
+from zope import schema
 
-from loops.interfaces import IExternalFile
+_ = MessageFactory('cybertools.media')
 
 
 class IMediaAsset(Interface):
 
+    modified = schema.Date(
+                title=_(u'Date'),
+                description=_(u'The date/time the picture was taken.'),
+                required=False,)
+
     def getData(variant=None):
         """ Return the binary data of the media asset or one of its variants.
         """