diff --git a/docs/index.rst b/docs/index.rst
index 05f3eb85..b2b42fe9 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -10,6 +10,8 @@ viASP can be used via the command line or its Python API.
    comment viASP uses the clingo python API, a Flask server and a Dash frontend to generate the visualizations.
 
 .. image:: ./img/header.png
+   :width: 100%
+   :alt: viASP header
 
 Explore ASP programs and their answer sets with viASP: