diff --git a/make-overlay.py b/make-overlay.py
new file mode 100644
index 0000000..7f931b3
--- /dev/null
+++ b/make-overlay.py
@@ -0,0 +1,102 @@
+# Copyright (C) 2011 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Script to take a set of frames (PNG files) for a recovery
+"installing" icon animation and turn it into a base image plus a set
+of overlays, as needed by the recovery UI code.  Run with the names of
+all the input frames on the command line, in order."""
+
+import sys
+try:
+  import Image
+except ImportError:
+  print "This script requires the Python Imaging Library to be installed."
+  sys.exit(1)
+
+# Find the smallest box that contains all the pixels which change
+# between images.
+
+print "reading", sys.argv[1]
+base = Image.open(sys.argv[1])
+
+minmini = base.size[0]-1
+maxmaxi = 0
+minminj = base.size[1]-1
+maxmaxj = 0
+
+for top_name in sys.argv[2:]:
+  print "reading", top_name
+  top = Image.open(top_name)
+
+  assert base.size == top.size
+
+  mini = base.size[0]-1
+  maxi = 0
+  minj = base.size[1]-1
+  maxj = 0
+
+  h, w = base.size
+  for j in range(w):
+    for i in range(h):
+      b = base.getpixel((i,j))
+      t = top.getpixel((i,j))
+      if b != t:
+        if i < mini: mini = i
+        if i > maxi: maxi = i
+        if j < minj: minj = j
+        if j > maxj: maxj = j
+
+  minmini = min(minmini, mini)
+  maxmaxi = max(maxmaxi, maxi)
+  minminj = min(minminj, minj)
+  maxmaxj = max(maxmaxj, maxj)
+
+w = maxmaxi - minmini + 1
+h = maxmaxj - minminj + 1
+
+# Now write out an image containing just that box, for each frame.
+
+for num, top_name in enumerate(sys.argv[1:]):
+  top = Image.open(top_name)
+
+  out = Image.new("RGB", (w, h))
+  for i in range(w):
+    for j in range(h):
+      t = top.getpixel((i+minmini, j+minminj))
+      out.putpixel((i, j), t)
+
+  fn = "icon_installing_overlay%02d.png" % (num+1,)
+  out.save(fn)
+  print "saved", fn
+
+# Write out the base icon, which is the first frame with that box
+# blacked out (just to make the file smaller, since it's always
+# displayed with one of the overlays on top of it).
+
+for i in range(w):
+  for j in range(h):
+    base.putpixel((i+minmini, j+minminj), (0, 0, 0))
+fn = "icon_installing.png"
+base.save(fn)
+print "saved", fn
+
+# The device_ui_init() function needs to tell the recovery UI the
+# position of the overlay box.
+
+print
+print "add this to your device_ui_init() function:"
+print "-" * 40
+print "  ui_parameters->install_overlay_offset_x = %d;" % (minmini,)
+print "  ui_parameters->install_overlay_offset_y = %d;" % (minminj,)
+print "-" * 40