|PhotoScale! is an image scaling tool, it allows you to resize whole directories of images to mostly any(reasonable) resolution and also convert them to different image formats.
It's an ideal tool when you have to upload to the web huge amounts of pictures. Most social networking sites use quite low image resolutions and uploading 3072x2304 (7 megapixels, approximately 4.5 megabytes) pictures is both a waste of time and bandwidth.
For example, Fotolog.com uses a resolution of 500x375 (~20 kB), uploading your 5mb picture over a 1 Mb connection would take ages (most upload speeds are under 100 kb/s, mine is about 20 kb/s). If you scale the picture before uploading, the transfer takes almost nothing!