diff --git a/contrib/templates/default/modpage.mustache b/contrib/templates/default/modpage.mustache
index 93ed7c6..b3287bf 100644
--- a/contrib/templates/default/modpage.mustache
+++ b/contrib/templates/default/modpage.mustache
@@ -38,7 +38,7 @@
       <label>very load heavy actions, use with care</label>
       <div>
         <button onclick="nntpchan_admin('frontend.regen', {})">regenerate all pages</button>
-        <button onclick="nntpchan_admin('thumbnail.regen', {})">regenerate all thumbnails</button>
+        <button onclick="nntpchan_admin('thumbnail.regen', {threads:1})">regenerate all thumbnails</button>
       </div>
     </div>  
     <div id="nntpchan_mod_result"></div>