diff --git a/imagekit/options.py b/imagekit/options.py
index 7170799..f3d3820 100644
--- a/imagekit/options.py
+++ b/imagekit/options.py
@@ -14,7 +14,7 @@ class Options(object):
     cache_dir = 'cache'
     save_count_as = None
     cache_filename_fields = ['pk', ]
-    cache_filename_format = "%(filename)s_%(specname)s.%(extension)s"
+    cache_filename_format = "%(filename)s_%(specname)s_%(original_extension)s.%(extension)s"
     admin_thumbnail_spec = 'admin_thumbnail'
     spec_module = 'imagekit.defaults'
     specs = None
diff --git a/imagekit/specs.py b/imagekit/specs.py
index 0332187..49005a9 100644
--- a/imagekit/specs.py
+++ b/imagekit/specs.py
@@ -82,11 +82,13 @@ class Accessor(object):
         if self._obj._imgfield.name:
             filepath, basename = os.path.split(self._obj._imgfield.name)
             filename, extension = os.path.splitext(basename)
+	    original_extension = extension
             for processor in self.spec.processors:
                 if issubclass(processor, processors.Format):
                     extension = processor.extension
             filename_format_dict = {'filename': filename,
                                     'specname': self.spec.name(),
+				    'original_extension': original_extension,
                                     'extension': extension.lstrip('.')}
             cache_filename_fields = self._obj._ik.cache_filename_fields
             filename_format_dict.update(dict(zip(