Reduce image file sizes and improve performance using the Smush.it API within WordPress.
In theory this is a great plugin. But if you have an image heavy site with lots of large images, it won't help. Most images these days are much large than 1mb and, while it's true that users can downsample images locally, the point of this plugin is to make the process more streamlined especially for a WP site that has multiple 'lay' users.
I'd love to see a service that handles image compression for images with a 4-5mb file size, since this is pretty typical for images these days and that's were the bulk of image load time comes from.
It works but very slow, and sometimes erroneous.
I had to remove this plugin from production sites because of the inconsistent performance of the Yahoo API. The long term outlook of support for the API is not great, but this plugin would likely port well to other services.
Don't get me wrong this is the best image optimize plugin on WP BUT it has been getting more unstable over the past few months resulting in the point where I had to get it off my test site as it was causing timeouts, errors, server downtime and more. It seems from the support forum a number of people are experiencing errors which are historic and yet the plugin makers do not seem to be looking after it and listening to the issues people are having. Hence why I can only give it a three-star at this time.
I do hope Yahoo get into gear and give the support this widely used and easy to use optimizer needs.