Fix Image when passing only data, and add tests.

Closes  #9181

IPython/core/display.py

@@ -12,7 +12,6 b' import os'
 import struct
 import warnings
 
-from IPython.core.formatters import _safe_get_formatter_method
 from IPython.utils.py3compat import (string_types, cast_bytes_py2, cast_unicode,
                                      unicode_type)
 from IPython.testing.skipdoctest import skip_doctest
@@ -731,14 +730,14 b' class Image(DisplayObject):'
                 if data[:2] == _JPEG:
                     format = self._FMT_JPEG
 
-        if format.lower() == 'jpg':
-            # jpg->jpeg
-            format = self._FMT_JPEG
-
         # failed to detect format, default png
         if format is None:
             format = 'png'
 
+        if format.lower() == 'jpg':
+            # jpg->jpeg
+            format = self._FMT_JPEG
+
         self.format = unicode_type(format).lower()
         self.embed = embed if embed is not None else (url is None)
 

IPython/core/tests/test_display.py

@@ -43,6 +43,9 b' def test_retina_jpeg():'
     nt.assert_equal(md['width'], 1)
     nt.assert_equal(md['height'], 1)
 
+def test_base64image():
+    display.Image("iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEUAAACnej3aAAAAAWJLR0QAiAUdSAAAAAlwSFlzAAALEwAACxMBAJqcGAAAAAd0SU1FB94BCRQnOqNu0b4AAAAKSURBVAjXY2AAAAACAAHiIbwzAAAAAElFTkSuQmCC")
+
 def test_image_filename_defaults():
     '''test format constraint, and validity of jpeg and png'''
     tpath = ipath.get_ipython_package_dir()