Online JPG Optimizer: JPEGmini

JPEGmini is a photo recompression technology, which reduces the file size of photos by up to 5X, without affecting their perceptual quality.

The JPEGmini guys have recently launched an online JPG optimizer service at JPEGmini.com, which enables users to process an unlimited number of photos for free using our JPEGmini technology.

The best part is that the resulting files are completely JPEG compatible, so they can be viewed on just about any device on the planet.