Fix ValueError: invalid PNG header on Windows

cgohlke · WeatherGod · commit 6107fb5df1f6 · 2015-10-05T14:10:39.000-04:00
On Windows the `urlparse(...).scheme != ''` test for URLs does not work.
For file names the drive letter is returned as scheme.
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -1287,7 +1287,7 @@ def pilread(fname):
         if cbook.is_string_like(fname):
             parsed = urlparse(fname)
             # If the string is a URL, assume png
-            if parsed.scheme != '':
+            if len(parsed.scheme) > 1:
                 ext = 'png'
             else:
                 basename, ext = os.path.splitext(fname)
