diff --git a/src/themes/cleanblog/templates/article.html b/src/themes/cleanblog/templates/article.html
index 8e7956e..7685125 100755
--- a/src/themes/cleanblog/templates/article.html
+++ b/src/themes/cleanblog/templates/article.html
@@ -33,7 +33,7 @@
     {% if article.header_cover %}
         <header class="intro-header" style="background-image: url('{{ article.header_cover }}')">
     {% else %}
-        <header class="intro-header" style="background-image: url('{{ SITEURL }}/{{ THEME_STATIC_DIR }}/images/post-bg.jpg')">
+        <header class="intro-header" style="background-image: url('{{ SITEURL }}/{{ THEME_STATIC_DIR }}/images/post-bg.png')">
     {% endif %}
         <div class="container">
             <div class="row">