diff --git a/chunk.py b/chunk.py
index d7505c6..19e72b4 100644
--- a/chunk.py
+++ b/chunk.py
@@ -60,17 +60,6 @@ def render_and_save(chunkfile, cave=False):
         # propagate the exception back to the parent process.
         raise Exception()
 
-def valid_image(filename):
-    """Returns true if the file is valid, false if it can't be loaded (is
-    corrupt or something)
-    """
-    try:
-        img = Image.open(filename)
-        img.load()
-    except Exception, e:
-        return False
-    return True
-
 class ChunkRenderer(object):
     def __init__(self, chunkfile):
         if not os.path.exists(chunkfile):
@@ -140,11 +129,7 @@ class ChunkRenderer(object):
             if os.path.getmtime(self.chunkfile) < os.path.getmtime(oldimg_path):
                 # chunkfile is older than the image, don't even bother checking
                 # the hash
-                if valid_image(oldimg_path):
-                    return oldimg_path
-                else:
-                    os.unlink(oldimg_path)
-                    oldimg = None
+                return oldimg_path
 
         # Reasons for the code to get to this point:
         # 1) An old image doesn't exist
@@ -163,7 +148,7 @@ class ChunkRenderer(object):
         dest_path = os.path.join(destdir, dest_filename)
 
         if oldimg:
-            if dest_filename == oldimg and valid_image(dest_path):
+            if dest_filename == oldimg:
                 # There is an existing file, the chunk has a newer mtime, but the
                 # hashes match.
                 return dest_path
@@ -175,7 +160,11 @@ class ChunkRenderer(object):
         # Render the chunk
         img = self.chunk_render(cave=cave)
         # Save it
-        img.save(dest_path)
+        try:
+            img.save(dest_path)
+        except:
+            os.unlink(dest_path)
+            raise
         # Return its location
         return dest_path
 
diff --git a/gmap.py b/gmap.py
index 69b25f3..20a7584 100755
--- a/gmap.py
+++ b/gmap.py
@@ -43,7 +43,9 @@ def main():
             if i > 0:
                 if 1000 % i == 0 or i % 1000 == 0:
                     print "{0}/{1} chunks rendered".format(i, len(chunks))
-    
+
+    results['pool'].join()
+
     print "Writing out html file"
     if not os.path.exists(destdir):
         os.mkdir(destdir)
diff --git a/world.py b/world.py
index 6fa893e..7e480e2 100644
--- a/world.py
+++ b/world.py
@@ -299,7 +299,22 @@ def render_worldtile(chunkmap, colstart, colend, rowstart, rowend, oldhash):
     # col colstart will get drawn on the image starting at x coordinates -(384/2)
     # row rowstart will get drawn on the image starting at y coordinates -(192/2)
     for col, row, chunkfile in tilelist:
-        chunkimg = Image.open(chunkfile)
+        try:
+            chunkimg = Image.open(chunkfile)
+        except IOError, e:
+            print "Error opening file", chunkfile
+            print "Attempting to re-generate it"
+            os.unlink(chunkfile)
+            # Do some string manipulation to determine what the chunk file is
+            # that goes with this image. Then call chunk.render_and_save
+            dirname, imagename = os.path.split(chunkfile)
+            parts = imagename.split(".")
+            datafile = "c.{0}.{1}.dat".format(parts[1],parts[2])
+            print "Chunk came from data file", datafile
+            # XXX Don't forget to set cave mode here when it gets implemented!
+            chunk.render_and_save(os.path.join(dirname, datafile), False)
+            chunkimg = Image.open(chunkfile)
+            print "Success"
 
         xpos = -192 + (col-colstart)*192
         ypos = -96 + (row-rowstart)*96
@@ -635,13 +650,21 @@ class ReturnableProcess(multiprocessing.Process):
         multiprocessing.Process.__init__(self, *args, **kwargs)
 
     def run(self):
-        results = self._target(*self._args, **self._kwargs)
-        self._respipe_in.send(results)
-        self.__sem.release()
+        try:
+            results = self._target(*self._args, **self._kwargs)
+        except BaseException, e:
+            self._respipe_in.send(e)
+        else:
+            self._respipe_in.send(results)
+        finally:
+            self.__sem.release()
 
     def get(self):
         self.join()
-        return self._respipe_out.recv()
+        ret = self._respipe_out.recv()
+        if isinstance(ret, BaseException):
+            raise ret
+        return ret
 
     def start(self):
         self._respipe_out, self._respipe_in = multiprocessing.Pipe()