A file that's both an acceptable HTML page and a JPEG (view source on it)
trick summary:<p>enter in you jpeg comment field: "<html>...your page...</html><!--"<p>then the "image" will look like:<p><pre><code>   @^PJFIF^@^A^A^A^A,^A,^@^@000^Cr<html>...your page...</html><!-- rest of garbage
</code></pre>
to the browser this is just the same as:<p><pre><code>   \n
   \n
   \n
   <html>...your page...</html></code></pre>