The Numeric File Renamer application will allow you to take a directory of files and rename them based on a sequential number. You can easily resequence already numerically named files, or rename them to a new sequential order. Add padding, prefix and sufix information, and even a new file extension if necessary.
You may rename all files in the selected folder, or limit the files with any standard file pattern, such as pages_*.tif, *.jpg;*.bmp and more.