Index: images.py
===================================================================
--- images.py	(revision 11108)
+++ images.py	(working copy)
@@ -32,21 +32,31 @@
     """Returns the (width, height) of an image, given an open file or a path."""
     from PIL import ImageFile as PILImageFile
     p = PILImageFile.Parser()
-    close = False
+
     if hasattr(file_or_path, 'read'):
         file = file_or_path
+        file_pos = file.tell()
+        file.seek(0)
+        we_opened_this_file = False
     else:
         file = open(file_or_path, 'rb')
-        close = True
-    try:
-        while 1:
-            data = file.read(1024)
-            if not data:
-                break
-            p.feed(data)
-            if p.image:
-                return p.image.size
-        return None
-    finally:
-        if close:
-            file.close()
+        we_opened_this_file = True
+
+    def file_cleanup():
+        if we_opened_this_file:
+          file.close()
+        else:
+          file.seek(file_pos)
+
+
+    while 1:
+        data = file.read(1024)
+        if not data:
+            break
+        p.feed(data)
+        if p.image:
+            file_cleanup()
+            return p.image.size
+
+    file_cleanup()
+    return None