diff --git a/activity/activity.info b/activity/activity.info
index 528e6bd..e0dcd5d 100644
--- a/activity/activity.info
+++ b/activity/activity.info
@@ -5,5 +5,5 @@ icon = activity-read
 exec = sugar-activity readactivity.ReadActivity
 show_launcher = no
 activity_version = 63
-mime_types = application/pdf;image/vnd.djvu;image/x.djvu;image/tiff
+mime_types = application/pdf;image/vnd.djvu;image/x.djvu;image/tiff;application/x-cbz;application/x-cbr
 license = GPLv2+
diff --git a/readactivity.py b/readactivity.py
index bc78e72..b68c241 100644
--- a/readactivity.py
+++ b/readactivity.py
@@ -272,8 +272,9 @@ class ReadActivity(activity.Activity):
     def read_file(self, file_path):
         """Load a file from the datastore on activity start."""
         _logger.debug('ReadActivity.read_file: %s', file_path)
+        extension = os.path.splitext(file_path)[1]
         tempfile = os.path.join(self.get_activity_root(), 'instance',
-                                'tmp%i' % time.time())
+                                'tmp%i%s' % (time.time(), extension))
         os.link(file_path, tempfile)
         self._tempfile = tempfile
         self._load_document('file://' + self._tempfile)