diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index 66e63a01..afe94e76 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -2013,6 +2013,16 @@ def new_workout_from_file(r, f2,
         return -1, message, f2
 
     # Some people try to upload Concept2 logbook summaries
+    if fileformat == 'imageformat':
+        os.remove(f2)
+        message = "You cannot upload image files here"
+        return (0, message, f2)
+
+    if fileformat == 'json':
+        os.remove(f2)
+        message = "JSON format not supported in direct upload"
+        return (0, message, f2)
+
     if fileformat == 'c2log':
         os.remove(f2)
         message = "This  summary does not contain stroke data. Use the files containing stroke by stroke data."