Virtually any photo manager lets you perform mundane tasks like adjusting contrast, adding a watermark, and applying effects to your photos. But even powerful applications like digiKam and F-Spot can't really help you when you need to perform the same action (or a sequence of actions) on dozens or hundreds of photos. For that you need a batch processing utility like Phatch. This nifty tool can perform no fewer than 35 different actions on your photos, and its user-friendly graphical interface makes it easy to create advanced multistep batch rules.
Phatch is a simple to use cross-platform GUI Photo Batch Processor which handles all popular image formats and can duplicate (sub)folder hierarchies. Phatch can batch resize, rotate, rename, … and more in minutes instead of hours or days if you do it manually. Phatch will also support a console version in the future to batch photos on webservers.
Renaming a big set of files can be a right chore. For example, if you’ve just imported a set of digital photos, they’ll usually have really unhelpful and undescriptive filenames such as DSC_0000.jpg.