add alt labels to images

theme/templates/page.html

@@ -22,9 +22,9 @@
                 {% endif %}
                 <li><a href="https://tickets.hackenopenair.de">Presale</a></li>
                 {% if content.group == "en" %}
-                    <li><a href="/index.html"><img src="/static/img/de.png"></a></li>
+                    <li><a href="/index.html" aria-label="diese Seite auf Deutsch"><img src="/static/img/de.png" alt="german"></a></li>
                 {% else %}
-                    <li><a href="/en.html"><img src="/static/img/gb.png"></a></li>
+                    <li><a href="/en.html" aria-label="this page in english"><img src="/static/img/gb.png" alt="englisch"></a></li>
                 {% endif %}
             </ul>
         </nav>
@@ -33,7 +33,7 @@
 <div class="main">
     <div align="center">
         <h3>02.08. - 05.08. 2018 in Rötgesbüttel</h3>
-        <img id="specht" src="/static/img/specht.svg">
+        <img id="specht" src="/static/img/specht.svg" alt="logo">
     </div>
 
     {{ content.content_body }}