Remove links on image credits with no creditlink

_layouts/post.html

@@ -14,7 +14,7 @@
 
 {% if page.image.feature %}
 <div class="entry-header">
-  {% if page.image.credit %}<div class="image-credit">Image source: <a href="{{ page.image.creditlink }}">{{ page.image.credit }}</a></div><!-- /.image-credit -->{% endif %}
+  {% if page.image.credit %}<div class="image-credit">Image source: {% if page.image.creditlink %}<a href="{{ page.image.creditlink }}">{% endif %}{{ page.image.credit }}{% if page.image.creditlink %}</a>{% endif %}</div><!-- /.image-credit -->{% endif %}
   <div class="entry-image">
     <img src="{{ site.url }}/images/{{ page.image.feature }}" alt="{{ page.title }}">
   </div><!-- /.entry-image -->