Admin/website/overview.html

       eases the task of writing and maintaining proof scripts.</p>
       <br clear="all" />
 
       <h2>Preview</h2>
 
-      <p>We provide a <a href="PG-preview.mov">hyperlinked preview</a> demonstrating
+      <p>We provide a <a href="//media/PG-preview.mov">hyperlinked preview</a> demonstrating
       Isabelle and ProofGeneral, in <a href="http://www.apple.com/quicktime/download/">QuickTime
-      format</a>, and also as a <a href="PG-preview.pdf">non-hyperlinked preview</a> in PDF.</p>
+      format</a>, and also as a <a href="//media/PG-preview.pdf">non-hyperlinked preview</a> in PDF.</p>
     
       <p>Ample <a href="dist/documentation.html">documentation</a> is available
       about using Isabelle and its inner concepts, including a
       <a href="http://www4.in.tum.de/~nipkow/LNCS2283/">Tutorial</a> published by
       Springer-Verlag.</p>