It wraps ImageMagick to perform the image transformations.
PhotoCatUtil has several important concepts:
What can they tell you? Well if you have your camera properly set up, it knows when you took the picture. Now this is useful!
You may wonder why you care, after all, the file already has a date-stamp on it. That is true. And it's even accurate as long as you do not modify the image. Once it is re-written by a graphics program, that date has changed. So, PhotoCatUtil renames a file when Copies/Moves it from the camera (i.e. media, could be any device, really) to storage (the place you keep the raw images that you will keep in case you want to reprocess them in the future.)