diff --git a/README.rst b/README.rst
index f3f23b9..3164ef7 100644
--- a/README.rst
+++ b/README.rst
@@ -246,6 +246,15 @@ Options
 --night
     This option enables --lighting, and renders the world at night.
 
+--web-assets-hook=HOOK
+    This option lets you specify a script to run after the web assets have been
+    copied into the output directory, but before any tile rendering takes
+    place. This is an ideal time to do any custom postprocessing for markers.js
+    or other web assets.
+    
+    The script should be executable, and it should accept one argument:
+    the path to the output directory.
+
 Viewing the Results
 -------------------
 Within the output directory you will find two things: an index.html file, and a
diff --git a/gmap.py b/gmap.py
index f864526..50b6822 100755
--- a/gmap.py
+++ b/gmap.py
@@ -24,6 +24,7 @@ import os
 import os.path
 from configParser import ConfigOptionParser
 import re
+import subprocess
 import multiprocessing
 import time
 import logging
@@ -62,6 +63,7 @@ def main():
     parser.add_option("--rendermode", dest="rendermode", help="Specifies the render type: normal (default), lighting, night, or spawn.", type="choice", choices=["normal", "lighting", "night", "spawn"], required=True, default="normal")
     parser.add_option("--imgformat", dest="imgformat", help="The image output format to use. Currently supported: png(default), jpg. NOTE: png will always be used as the intermediate image format.", configFileOnly=True )
     parser.add_option("--optimize-img", dest="optimizeimg", help="If using png, perform image file size optimizations on the output. Specify 1 for pngcrush, 2 for pngcrush+optipng+advdef. This may double (or more) render times, but will produce up to 30% smaller images. NOTE: requires corresponding programs in $PATH or %PATH%", configFileOnly=True)
+    parser.add_option("--web-assets-hook", dest="web_assets_hook", help="If provided, run this script after the web assets have been copied, but before actual tile rendering begins. See the README for details.", action="store", metavar="SCRIPT", type="string", configFileOnly=True)
     parser.add_option("-q", "--quiet", dest="quiet", action="count", default=0, help="Print less output. You can specify this option multiple times.")
     parser.add_option("-v", "--verbose", dest="verbose", action="count", default=0, help="Print more output. You can specify this option multiple times.")
     parser.add_option("--skip-js", dest="skipjs", action="store_true", help="Don't output marker.js or regions.js")
@@ -138,7 +140,22 @@ def main():
         optimizeimages.check_programs(optimizeimg)
     else:
         optimizeimg = None
-
+    
+    if options.web_assets_hook:
+        if not os.path.exists(options.web_assets_hook):
+            parser.error("Provided hook script does not exist!")
+    def web_assets_hook(quadtree):
+        if options.web_assets_hook == None:
+            return
+        try:
+            subprocess.check_call((options.web_assets_hook, os.path.abspath(quadtree.destdir)))
+        except OSError, e:
+            logging.error("could not call web assets hook: %s" % (e,))
+            sys.exit(1)
+        except subprocess.CalledProcessError:
+            logging.error("web assets hook returned error")
+            sys.exit(1)
+    
     logging.getLogger().setLevel(
         logging.getLogger().level + 10*options.quiet)
     logging.getLogger().setLevel(
@@ -160,7 +177,7 @@ def main():
 
     # Now generate the tiles
     # TODO chunklist
-    q = quadtree.QuadtreeGen(w, destdir, depth=options.zoom, imgformat=imgformat, optimizeimg=optimizeimg, rendermode=options.rendermode)
+    q = quadtree.QuadtreeGen(w, destdir, depth=options.zoom, imgformat=imgformat, optimizeimg=optimizeimg, rendermode=options.rendermode, web_assets_hook=web_assets_hook)
     q.write_html(options.skipjs)
     q.go(options.procs)
 
diff --git a/quadtree.py b/quadtree.py
index 77361a2..ec97e50 100644
--- a/quadtree.py
+++ b/quadtree.py
@@ -90,7 +90,7 @@ def pool_initializer(quadtree):
     child_quadtree = quadtree    
     
 class QuadtreeGen(object):
-    def __init__(self, worldobj, destdir, depth=None, tiledir="tiles", imgformat=None, optimizeimg=None, rendermode="normal"):
+    def __init__(self, worldobj, destdir, depth=None, tiledir="tiles", imgformat=None, optimizeimg=None, rendermode="normal", web_assets_hook=None):
         """Generates a quadtree from the world given into the
         given dest directory
 
@@ -103,6 +103,7 @@ class QuadtreeGen(object):
         assert(imgformat)
         self.imgformat = imgformat
         self.optimizeimg = optimizeimg
+        self.web_assets_hook = web_assets_hook
         
         self.lighting = rendermode in ("lighting", "night", "spawn")
         self.night = rendermode in ("night", "spawn")
@@ -196,6 +197,8 @@ class QuadtreeGen(object):
             output.write(index)
 
         if skipjs:
+            if self.web_assets_hook:
+                self.web_assets_hook(self)
             return
 
         # since we will only discover PointsOfInterest in chunks that need to be 
@@ -224,6 +227,9 @@ class QuadtreeGen(object):
             output.write('  // ]},\n')
             output.write('];')
         
+        if self.web_assets_hook:
+            self.web_assets_hook(self)
+        
     def _get_cur_depth(self):
         """How deep is the quadtree currently in the destdir? This glances in
         config.js to see what maxZoom is set to.