diff --git a/IPython/sphinxext/ipython_directive.py b/IPython/sphinxext/ipython_directive.py
index 0481624..3d5b376 100644
--- a/IPython/sphinxext/ipython_directive.py
+++ b/IPython/sphinxext/ipython_directive.py
@@ -419,8 +419,8 @@ class EmbeddedSphinxShell(object):
         # insert relative path to image file in source 
         # as absolute path for Sphinx
         # sphinx expects a posix path, even on Windows
-        posix_path = pathlib.Path(savefig_dir,filename).as_posix()
-        outfile = '/' + os.path.relpath(posix_path, source_dir)
+        path = pathlib.Path(savefig_dir, filename)
+        outfile = '/' + path.relative_to(source_dir).as_posix()
 
         imagerows = ['.. image:: %s' % outfile]