title: why png size doesn't change after using http gzip compression
body: <p>I use following .htaccess to set gzip compression:</p>
  
  <pre><code>AddOutputFilterByType DEFLATE text/html image/png image/jpeg text/css text/javascript
  </code></pre>
  
  <p>Please check this url: <a href="http://www.coinex.com/cn/silver_panda/proof/china_1984_27_gram_silver_panda_coin/">http://www.coinex.com/cn/silver_panda/proof/china_1984_27_gram_silver_panda_coin/</a></p>
  
  <p>the gzip compression works for html, css, js and jpg, but not working for png (really amazing..)</p>