This program can be very useful when renaming ' image.jpg ' files created by a digital camera. You can chose any name for all the files in a directory with a selected EXT. A number will be added to end of the filename. It can also shorten filenames from the right to a chosen length, or insert say a number prefix to selected files, or change to lower case with the first letter upper case. It will NOT allow files in the Windows or Program files to be changed.