fix crash on loading corrupted image by PIL

sphinxcontrib/plantuml.py

@@ -270,10 +270,16 @@ def _get_png_tag(self, fnames, node):
 
  # Add physical size to assist rendering (defaults)
  if not styles:
- im = Image.open(outfname)
- im.load()
- styles.extend('%s: %s%s' % (a, w * scale / 100, 'px')
- for a, w in zip(['width', 'height'], im.size))
+ # the image may be corrupted if platuml isn't configured correctly,
+ # which isn't a hard error.
+ try:
+ im = Image.open(outfname)
+ im.load()
+ styles.extend('%s: %s%s' % (a, w * scale / 100, 'px')
+ for a, w in zip(['width', 'height'], im.size))
+ except OSError as err:
+ logger.warning('plantuml: failed to get image size: %s'
+ % err)
 
  return ('<a href="%s"><img src="%s" alt="%s" style="%s"/>'
  '</a>\n'