fix double-encoding of png data

commit 046aebacca2386334f402099dc169a82875264c5 added b64 encoding of png data at the shell level, so the display formatter should *not* do this encoding itself.

also fix typo in InlineBackendConfig._figure_format_changed() method name.

IPython/lib/pylabtools.py

@@ -106,8 +106,6 b" def print_figure(fig, fmt='png'):"
     finally:
         fig.set_facecolor(fc)
         fig.set_edgecolor(ec)
-    if fmt == 'png':
-        data = data.encode('base64')
     return data
 
 

IPython/zmq/pylab/backend_inline.py

@@ -42,7 +42,7 b' class InlineBackendConfig(SingletonConfigurable):'
     figure_format = CaselessStrEnum(['svg', 'png'], default_value='png', config=True,
         help="The image format for figures with the inline backend.")
 
-    def _format_changed(self, name, old, new):
+    def _figure_format_changed(self, name, old, new):
         if self.shell is None:
             return
         else: