The Dynamic Drive image optimizing tool is fast, easy and free to use online.
Online Image Optimizer tool for GIF, JPG, and PNG lets you easily optimize your image files–gifs, animated gifs, jpgs, and pngs–so they load as fast as possible on your site. Furthermore, you can easily convert from one image type to another using this optimizer tool–http://tools.dynamicdrive.com/imageoptimizer/index.php
Use this free tool to enhance the color saturation of faded or washed-out looking low resolution jpegs used for making submissions.
It only takes a few seconds to upload each jpeg image into the Image Optimizer Tool and click the Optimize button for immediate results.
Use optimized images on your blog or website to speed-up image loading for your blog viewers.