diff --git a/extra_markdown.tpl b/extra_markdown.tpl
index 86e23ffb2a84fd013faecf1a6c5d8560907c3c5d..f9f94a4dd7368b5c4d8f75ce11a357c92322a05d 100644
--- a/extra_markdown.tpl
+++ b/extra_markdown.tpl
@@ -6,7 +6,7 @@
 {%- set fname = output.metadata.filenames['application/vnd.plotly.v1+json'] -%}
 {%- set plotly_url = fname | path2url -%}
 {%- set div_id = fname.split('/') | last -%}
-<div id="{{div_id}}"></div>
+<div id="{{div_id}}"><img ></img></div>
 
 <script>
 window.addEventListener('load', function() {
diff --git a/mkdocs.yml b/mkdocs.yml
index 6a68694abb072fb534ffe828ae48cd0e4dbb72bc..476e3ffbb84065a51eb856bc7be07f4d756d38da 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -4,7 +4,7 @@ repo_name: source
 edit_uri: edit/master/src/
 site_description: |
   Lecture notes for the TU Delft course TN2844 Solid state physics
-pages:
+nav:
   - Intro: 'index.md'
   - Phonons and specific Heat: 'lecture_1.md'
   - Free electron model: 'lecture_2.md'