ImageOptim removes EXIF metadata, such as GPS position and camera's serial number, so that you can publish images without exposing private information (but there's an option to keep the metadata if you need it).
Reduces image file sizes - so they take up less disk space and download faster - by applying advanced compression that preserves quality.
Removes invisible junk: private EXIF metadata from digital cameras, embedded thumbnails, comments, and unnecessary color profiles.
Seamlessly combines all the best image optimization tools: MozJPEG, Pngcrush, pngquant, 7zip and Google Zopfli. All Free and Open-Source.