diff --git a/PRESUBMIT.py b/PRESUBMIT.py
new file mode 100644
index 0000000..fc4cc71
--- /dev/null
+++ b/PRESUBMIT.py
@@ -0,0 +1,33 @@
+# Copyright 2017 The PDFium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Presubmit script for PDFium testing corpus.
+
+See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
+for more details about the presubmit API built into depot_tools.
+"""
+
+def _CheckPngNames(input_api, output_api):
+  """Checks that .png files have the right file name pattern"""
+  import re
+  png_regex = re.compile('.+_expected(_(win|mac|linux))?\.pdf\.\d+.png')
+  warnings = []
+  for f in input_api.AffectedFiles():
+    local_path = f.LocalPath()
+    if local_path.endswith('.png'):
+      if not png_regex.match(local_path):
+        warnings.append(local_path)
+
+  results = []
+  if warnings:
+    results.append(output_api.PresubmitPromptOrNotify(
+        'The following PNG files have the wrong file name format:\n',
+        warnings))
+  return results
+
+
+def CheckChangeOnUpload(input_api, output_api):
+  results = []
+  results += _CheckPngNames(input_api, output_api)
+  return results