Added IPythonViewer

Tests/test_imageshow.py

@@ -62,4 +62,20 @@ def test_viewer():
 
 def test_viewers():
     for viewer in ImageShow._viewers:
-        viewer.get_command("test.jpg")
+        try:
+            viewer.get_command("test.jpg")
+        except NotImplementedError:
+            pass
+
+
+def test_ipythonviewer():
+    pytest.importorskip("IPython", reason="IPython not installed")
+    for viewer in ImageShow._viewers:
+        if isinstance(viewer, ImageShow.IPythonViewer):
+            test_viewer = viewer
+            break
+    else:
+        assert False
+
+    im = hopper()
+    assert test_viewer.show(im) == 1

src/PIL/ImageShow.py

@@ -218,6 +218,20 @@ def get_command_ex(self, file, title=None, **options):
         return command, executable
 
 
+class IPythonViewer(Viewer):
+    def show_image(self, image, **options):
+        display(image)
+        return 1
+
+
+try:
+    from IPython.display import display
+except ImportError:
+    pass
+else:
+    register(IPythonViewer)
+
+
 if sys.platform not in ("win32", "darwin"):  # unixoids
     if shutil.which("display"):
         register(DisplayViewer)