Raise exception when trying to use -S with the image formatter.

2 files changed, 9 insertions, 1 deletions

diff --git a/pygments/cmdline.py b/pygments/cmdline.py
index de10debe..4d485b6e 100644
--- a/pygments/cmdline.py
+++ b/pygments/cmdline.py
@@ -281,7 +281,11 @@ def main(args=sys.argv):
             return 1
 
         arg = a_opt or ''
-        print fmter.get_style_defs(arg)
+        try:
+            print fmter.get_style_defs(arg)
+        except Exception, err:
+            print >>sys.stderr, 'Error:', err
+            return 1
         return 0
 
     # if no -S is given, -a is not allowed
diff --git a/pygments/formatters/img.py b/pygments/formatters/img.py
index 59b29008..5bff5d93 100644
--- a/pygments/formatters/img.py
+++ b/pygments/formatters/img.py
@@ -305,6 +305,10 @@ class ImageFormatter(Formatter):
             self.line_number_width = 0
         self.drawables = []
 
+    def get_style_defs(self, arg=''):
+        raise NotImplementedError('The -S option is meaningless for the image '
+                                  'formatter. Use -O style=<stylename> instead.')
+
     def _get_line_height(self):
         """
         Get the height of a line.