Some responses to prior comments.

Yes, the app is written in Java. This means it is a little slower to load than other apps. It executes fairly quickly, though. Since it saves time compared to renaming files manually, the load time seems a small price to pay.

Version 1.1 added the ability to specify a sequential number to be added to each file name included in the rename.

Compared to some of the other renamer apps out there, PSRenamer has the advantage of being freeware, having a simpler and more intuitive user interface, having built-in help, and having a cute icon!