EWWW Image Optimizer is described as 'A free image optimizing alternative to many of the other paid WordPress optimizers' and is an app in the Photos & Graphics category. There are more than 25 alternatives to EWWW Image Optimizer for a variety of platforms, including Online / Web-based, Mac, Windows, Wordpress and Linux. The best alternative is RIOT - Radical Image Optimization Tool, which is free. Other great apps like EWWW Image Optimizer are ImageOptim (Free Personal, Open Source), TinyPNG (Freemium), JPEGmini (Paid) and Optimage (Freemium).
Saving images for web/email/other media with the best compression ratio and quality is a difficult task if you don’t have the right tools. Choosing the right format then choosing the right parameters are the key factors of smaller files.
ImageOptim is excellent for publishing images on the web (easily shrinks images “Saved for Web” in Photoshop). It's useful for making Mac and iPhone/iPad applications smaller (if you configure Xcode to allow better optimization).
TinyPNG uses smart lossy compression techniques to reduce the file size of your PNG files. By selectively decreasing the number of colours in the image, fewer bytes are required to store the data. The effect is nearly invisible but it makes a very large difference in file size!
With Image Optimizer you can losslessly optimize your PNG, JPEG and GIF files and thus save your bandwidth and your users' time! Kraken recompresses images with blazing speed and strips metadata with image quality intact.