diff --git a/docs/conf.py b/docs/conf.py
index daa5e9913..7cd047a06 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -45,6 +45,7 @@ extensions = [
     'sphinx_a4doc',
     'html_extra_template_renderer',
     'remix_code_links',
+    'sphinx.ext.imgconverter',
 ]
 
 a4_base_path = os.path.dirname(__file__) + '/grammar'