Using optimization techniques recommended by Yahoo for best performance, WP Smush.it optimizes your images in several ways:
- stripping meta data from JPEGs
- optimizing JPEG compression
- converting certain GIFs to indexed PNGs
- stripping the un-used colours from indexed images
It does all of this behind the scenes whenever you upload or insert an image. By clicking on your Media Library, you can see how much each image has been reduced by to get an idea of the kind of performance boost it is giving you. The screenshot on the right is of the latest 7 images uploaded on Pippin’s Pages. While all 7 amount to little more than half a megabyte of savings, you can imagine how that can really add up with lots and lots of images.
I have been using WP Smush.it for the last 3-4 months on my site and have encountered zero problems with it. I’d recommend it to anyone.
The first time you install the plugin, you will have to navigate to your media library and tell it to go ahead and smush all the images already there, which, depending on how many you have, can take some time. After the initial smushing, it will perform the optimization for you automatically upon upload.
Link: WP Smush.it