Add png and jpg support to md_browser.

tools/md_browser/md_browser.py

Index: tools/md_browser/md_browser.py
diff --git a/tools/md_browser/md_browser.py b/tools/md_browser/md_browser.py
index 2c4164330aefb9a89452788c0e7e4cda08af205b..d3594bfe520c97ad810e9c63151122ab90c69824 100755
--- a/tools/md_browser/md_browser.py
+++ b/tools/md_browser/md_browser.py
@@ -138,6 +138,10 @@ class Handler(SimpleHTTPServer.SimpleHTTPRequestHandler):
       self._DoMD(path)
     elif os.path.exists(full_path + '/README.md'):
       self._DoMD(path + '/README.md')
+    elif path.lower().endswith('.png'):
+      self._DoImage(full_path, 'image/png')
+    elif path.lower().endswith('.jpg'):
+      self._DoImage(full_path, 'image/jpeg')
     else:
       self._DoDirListing(full_path)
 
@@ -223,6 +227,12 @@ class Handler(SimpleHTTPServer.SimpleHTTPRequestHandler):
 
     self._WriteTemplate('footer.html')
 
+  def _DoImage(self, full_path, mime_type):
+    self._WriteHeader(mime_type)
+    with open(full_path) as f:
+      self.wfile.write(f.read())
+      f.close()
+
   def _Read(self, relpath, relative_to=None):
     if relative_to is None:
       relative_to = self.server.top_level