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mod_pagespeed 2.1 is here — open source (Apache-2.0): the module you know, plus the optimizer worker

Recompress images in CSS

CSS

Recompresses images referenced from inside stylesheets.

Filter rewrite_css,rewrite_images · Filter docs

A module filter.

Original Open in new tab
Optimized Open in new tab

Both frames render identically — that's the goal. The win is in the bytes and requests below, not the look. They're served live by the mod_pagespeed module on demo-httpd-1.1.modpagespeed.com; the optimized frame applies only this filter. Right after a cache purge it may briefly match the original while the worker rewrites it — reload to see the result.

Measured impact

This filter changes how the page is structured or delivered, not its size — so there's no byte or request reduction to chart. The change shows in the source diff below.

What changed in the source

The page's HTML, before and after this filter. Red lines are removed, green lines are added. 

                
                  

                        <html>
                    

                          <head>
                    

                            <title>rewrite_images in CSS example</title>
                    

                      -     <style type='text/css'>
                    

                      -       body { background: url(images/Cuppa.png) no-repeat center; }
                    

                      -     </style>
                    

                      -     <link rel="stylesheet" type="text/css" href="styles/rewrite_css_images.css">
                    

                      +     <style type='text/css'>body{background:url(images/xCuppa.png.pagespeed.ic.FlgX5ioeLe.webp) no-repeat center}</style>
                    

                      +     <link rel="stylesheet" type="text/css" href="styles/A.rewrite_css_images.css.pagespeed.cf.Hyd81xUXhH.css">
                    

                          </head>
                    

                          <body>
                    

                            <p>The background image should be rewritten or cache extended.</p>

Run this on your own site

This is one of 49 filters the mod_pagespeed module applies in place — self-hosted on Apache, nginx, and IIS. Install and run it: it optimizes right away and adds an the optimized response headers shown above. Open source under the Apache License 2.0 — free in development and in production.

Download & run
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