Photo Crunch is useful to easily decrease the filesize of jpg images.

Just browse for a file and select a compression ratio from a drop-down picklist to view the results both in quality and file size.

Controlling the compression level is ideal for reducing the file size of JPG images. It's a good idea to do this for images that will be used on the World Wide Web, which will reduce download time considerably.

Compression levels around 50 and 60 are often perfectly acceptable on the Web. Images viewed with a 256-color display will see little difference between various compression levels above 50.