add reference to bmp.py

diff --git a/bmp.py b/bmp.py
index fc67e296d9641cd738d0ae994fc2d784a55141bf..e07719f673911b8ef58bdab07e096e0be2874d00 100644 (file)
--- a/bmp.py
+++ b/bmp.py
@@ -1,4 +1,5 @@
 # bmp - bitmap processing
+# ref: https://en.wikipedia.org/wiki/BMP_file_format
 
 from struct import unpack