Yahoo’s Smush.it service has recently begun to seriously throttle the connections to its service, making it (and the WP Smush.it plugin) essentially useless.
If you need to compress your images on your website, there are still tools available that will do the job automatically. Some bloggers may wish to compress their images on their home computer before uploading them to their sites. WordPress 3.5 has an improved image uploader makes it easy to upload multiple images at once.
EWWW Image Optimizer
The EWWW Image Optimizer plugin uses the jpegtran, optipng, pngout, and gifsicle image compression tools. The drawback is that it uses your server’s CPU to do the compression: performing server-based image compressions reduces the amount of server resources that are available to your visitors. EWWW Image Optimizer also requires the exec() php function, which might not be allowed depending upon your host.
Optimize the Images on your Desktop Computer
Compression services like Smush.it and Kraken (which currently doesn’t have a WordPress plugin) are great as far as convenience: you just upload your photos and you let an API service take care of compressing them. But you’ll get more control by optimizing your images on your home computer before you upload them. There are plenty of great freeware PNG and JPEG compressor’s for both Mac and Windows.
- Jpegmini is available for the Mac or to run on your server. It’s a lossy compressor, meaning that there is a slight reduction in quality that’s hard to notice. The Mac version is free while the server version has a licensing fee attached to it.
- If you need an all around image compressor that’s free and works with GIF, JPEG and PNG, try imageoptim on the Mac or Radical Image Optimization Tool on Windows.
- If you’re on Windows and only need to compress PNGs, then Png Gauntlet is a good choice.