diff --git a/odoo/addons/test_new_api/tests/test_new_fields.py b/odoo/addons/test_new_api/tests/test_new_fields.py
index 10993c52668..441362e7038 100644
--- a/odoo/addons/test_new_api/tests/test_new_fields.py
+++ b/odoo/addons/test_new_api/tests/test_new_fields.py
@@ -1953,11 +1953,18 @@ class TestFields(TransactionCaseWithUserDemo):
         self.assertEqual(image_data_uri(record.image_256)[:30], 'data:image/png;base64,iVBORw0K')
 
         # ensure invalid image raises
-        with self.assertRaises(UserError):
+        with self.assertRaises(UserError), self.cr.savepoint():
             record.write({
                 'image': 'invalid image',
             })
 
+        # assignment of invalid image on new record does nothing, the value is
+        # taken from origin instead (use-case: onchange)
+        new_record = record.new(origin=record)
+        new_record.image = '31.54 Kb'
+        self.assertEqual(record.image, image_h)
+        self.assertEqual(new_record.image, image_h)
+
     def test_95_binary_bin_size(self):
         binary_value = base64.b64encode(b'content')
         binary_size = b'7.00 bytes'
diff --git a/odoo/fields.py b/odoo/fields.py
index 7656b279004..324450bf80e 100644
--- a/odoo/fields.py
+++ b/odoo/fields.py
@@ -2113,7 +2113,18 @@ class Image(Binary):
         super(Image, self).create(new_record_values)
 
     def write(self, records, value):
-        new_value = self._image_process(value)
+        try:
+            new_value = self._image_process(value)
+        except UserError:
+            if not any(records._ids):
+                # Some crap is assigned to a new record. This can happen in an
+                # onchange, where the client sends the "bin size" value of the
+                # field instead of its full value (this saves bandwidth). In
+                # this case, we simply don't assign the field: its value will be
+                # taken from the records' origin.
+                return
+            raise
+
         super(Image, self).write(records, new_value)
         cache_value = self.convert_to_cache(value if self.related else new_value, records)
         records.env.cache.update(records, self, [cache_value] * len(records))