Do not fail if data property does not exist.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@14608 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/Image.py

@@ -146,7 +146,8 @@ class Image(File, OFSImage):
       self.data = self._data
 
     # Make sure size is defined
-    if not hasattr(aq_base(self), 'size') or not self.size:
+    if (not hasattr(aq_base(self), 'size') or not self.size) and \
+                      hasattr(aq_base(self), 'data'):
       self.size = len(self.data)
 
   security.declareProtected(Permissions.AccessContentsInformation, 'getWidth')