title: Tool for lossless image compression
body: <p>Running <a href="https://developers.google.com/speed/" rel="nofollow noreferrer">Google Page Speed</a> on a public site , I saw some suggestions by the tool like the following :</p>
  
  <p>Losslessly compressing <a href="http://g-ecx.images-amazon.com/images/G/01/electronics/detail-page/Acer-120x120._V137848950_.gi" rel="nofollow noreferrer">http://g-ecx.images-amazon.com/images/G/01/electronics/detail-page/Acer-120x120._V137848950_.gi</a> could save 4.8KiB (26% reduction) and they also provide a link to the  optimized content.But they do it on a per image basis. I saw some significant reduction on file sizes after compression. So the question is :</p>
  
  <p>Is there any tool or web service that I can use so that I give it a directory of uncompressed images(say .gif) and it returns me a directory of images with all of them compressed?</p>
  
  <p>I found a somewhat related question on SO <a href="https://stackoverflow.com/questions/5451597/how-does-googles-page-speed-lossless-image-compression-work">here</a> but it is not an exact duplicate.</p>
  
  <p>Thanks for reading.</p>