#!/bin/bash

prefix="Milleran-"
postfix=".jpg"
targetDir="./"
paddingLength=3

for file in ${prefix}[0-9]*${postfix}; do
  # strip the prefix off the file name
  postfile=${file#$prefix}
  # strip the postfix off the file name
  number=${postfile%$postfix}
  # subtract 1 from the resulting number
  i=(${number} -1)
  echo $(printf $prefix%0${paddingLength}d$postfix $i)
  # copy to a new name with padded zeros in a new folder
  #cp ${file} "$targetDir"/$(printf $prefix%0${paddingLength}d$postfix $i)
  mv ${file} $(printf $prefix%0${paddingLength}d$postfix $i)
done