--- a/src/pyams_file/image.py	Wed Feb 06 09:39:28 2019 +0100
+++ b/src/pyams_file/image.py	Wed Feb 06 09:45:52 2019 +0100
@@ -128,7 +128,10 @@
         else:
             return None
         # check format
-        image = Image.open(self.context.get_blob(mode='r'))
+        blob = self.context.get_blob(mode='r')
+        if blob is None:
+            return None
+        image = Image.open(blob)
         if not format:
             format = image.format
         format = format.upper()