(Jack:) Recognize PNG files.
diff --git a/Lib/imghdr.py b/Lib/imghdr.py
index f3137c5..c320594 100644
--- a/Lib/imghdr.py
+++ b/Lib/imghdr.py
@@ -94,6 +94,18 @@
 
 tests.append(test_jpeg)
 
+def test_bmp(h, f):
+	if h[:2] == 'BM':
+		return 'bmp'
+		
+tests.append(test_bmp)
+
+def test_png(h, f):
+	if h[:8] == "\211PNG\r\n\032\n":
+		return 'png'
+
+tests.append(test_png)
+
 #--------------------#
 # Small test program #
 #--------------------#