diff --git a/product/ERP5/Document/Image.py b/product/ERP5/Document/Image.py
index b02f44cebc764e799000a10f6c9f42e258907738..a87f5156797394115cccdcfba5b2aa031b778a72 100644
--- a/product/ERP5/Document/Image.py
+++ b/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')