Update README.rst

Author: Armand Foucault

README.rst

@@ -150,9 +150,9 @@ afterward will plot the result, making plots (using matplotlib) similar to these
    :target: https://github.com/scikit-learn/scikit-learn/pull/2248
    :height: 350px
 
-or, with the ``--flame`` option (``mprof plot --flame``):
+or, with ``mprof plot --flame`` (the function and timestamp names will appear on hover):
 
-.. image:: images/flamegraph.py
+.. image:: ./images/flamegraph.png
    :height: 350px
 
 A discussion of these capabilities can be found `here <http://fa.bianp.net/blog/2014/plot-memory-usage-as-a-function-of-time/>`_.