Index: lib/python/App/ImageFile.py
===================================================================
--- lib/python/App/ImageFile.py	(revision 72248)
+++ lib/python/App/ImageFile.py	(working copy)
@@ -15,7 +15,9 @@
 __version__='$Revision: 1.20 $'[11:-2]
 
 import os
+import stat
 import time
+import os.path
 
 from App.config import getConfiguration
 from zope.app.content_types import guess_content_type
@@ -25,6 +27,8 @@
 import Acquisition
 import Globals
 
+from ZPublisher.Iterators import filestream_iterator
+
 class ImageFile(Acquisition.Explicit):
     """Image objects stored in external files."""
 
@@ -43,17 +47,25 @@
             max_age = 3600 # One hour
         self.cch = 'public,max-age=%d' % max_age
 
-        data = open(path, 'rb').read()
+        img = open(path, 'rb')
+        data = img.read(1<<16) # 65k should be enough.
+        img.close()
+
         content_type, enc=guess_content_type(path, data)
         if content_type:
             self.content_type=content_type
         else:
-            self.content_type='image/%s' % path[path.rfind('.')+1:]
-        self.__name__=path[path.rfind('/')+1:]
-        self.lmt=float(os.stat(path)[8]) or time.time()
-        self.lmh=rfc1123_date(self.lmt)
+            ext = os.path.splitext(path)[-1].replace('.', '')
+            self.content_type='image/%s' %  ext
 
+        self.__name__ = os.path.split(path)[-1]
+        stat_info = os.stat(path)
+        self.size = stat_info[stat.ST_SIZE]
+        self.lmt = float(stat_info[stat.ST_MTIME]) or time.time()
+        self.lmh = rfc1123_date(self.lmt)
+        print path, self.content_type, self.size
 
+
     def index_html(self, REQUEST, RESPONSE):
         """Default document"""
         # HTTP If-Modified-Since header handling. This is duplicated
@@ -62,7 +74,8 @@
         RESPONSE.setHeader('Content-Type', self.content_type)
         RESPONSE.setHeader('Last-Modified', self.lmh)
         RESPONSE.setHeader('Cache-Control', self.cch)
-        header=REQUEST.get_header('If-Modified-Since', None)
+        RESPONSE.setHeader('Content-Length', str(self.size).replace('L', ''))
+        header = REQUEST.get_header('If-Modified-Since', None)
         if header is not None:
             header=header.split(';')[0]
             # Some proxies seem to send invalid date strings for this
@@ -82,7 +95,7 @@
                     RESPONSE.setStatus(304)
                     return ''
 
-        return open(self.path,'rb').read()
+        return filestream_iterator(self.path, mode='rb')
 
     HEAD__roles__=None
     def HEAD(self, REQUEST, RESPONSE):