FIX: add escape characters

Author: miykael

notebooks/introduction_python.ipynb

@@ -4,7 +4,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "<center><img src="../static/images/python.png" width=400></center>\n",
+    "<center><img src=\"../static/images/python.png\" width=500></center>\n",
     "\n",
     "# Python\n",
     "\n",