Let's assume you have OS X screenshots named like Screen Shot 2015-06-09 at 9.39.56 AM.png
. You can use this script to rename them like so:
mark:screens mark$ ruby renamer.rb
move ./Screen Shot 2015-06-09 at 9.39.56 AM.png to EXAMPLE_ONE_160x600_1.png
move ./Screen Shot 2015-06-09 at 9.39.57 AM.png to EXAMPLE_ONE_160x600_2.png
move ./Screen Shot 2015-06-09 at 9.39.58 AM.png to EXAMPLE_ONE_160x600_3.png
move ./Screen Shot 2015-06-09 at 9.40.00 AM.png to EXAMPLE_ONE_160x600_4.png