Free web app JPEGmini can quickly take your JPEG images and reduce their file sizes by up to 80 per cent -- all within your browser and while preserving their image quality.
We've previously featured great image compression tools like RIOT that serve the same purpose, but JPEGmini is unique in that you don't have to install anything. It works very simply and surprisingly fast: upload your image and the web app automatically compresses it, showing you a side-by-side view of the original and the compressed image.
The app only works with JPEGs, but it's handy for quickly shrinking your photo sizes so you can email them faster. The file size savings can be very dramatic.
Registering for a free account gives you more features like uploading full albums and sharing on Picasa and Flickr.