It's the successor to Image Compressor, a very popular free photo/file downloader (Mac) and also a very decent application for editing photos. It's an extremely easy to use, fast and user-friendly software. In Cesium, you can compress images either to save space or to compress larger pictures to save on disk space. It also supports many image supported formats, such as JPEG2000, JPEG2000T, FIF and GIFv1. The best part is that it's super easy to use. You just hit “Save” and the software does the rest. Cesium Image Compressor also features a customizable workflow that allows you to customize how it operates and how your photos are compressed; and can run on pretty much any computer without any special hardware, including Macs and Windows computers. This software is also a free download, so you can also check out the Cesium software for Windows Cesium is definitely a good, free tool for those of us who like to use free software. You can learn more about its features in its features comparison page. Cesium is available for Windows, Mac, and Linux.