The JPEG Reducer

The JPEG Reducer helps you to reduce the size of many JPEG files without any loss in the quality of the native image.

The program automatically detects binary duplicates among these files and automatically detects JPEG files which hold the same image, but are no binary duplicates for any reason, such as different DPI or meta data.
Also the program reveals matching images between two sets of files. If you're tired of finding out if certain images are already present in your collection, this program is for you.