How to Automate Cropping Images?
You may use ImageMagick in order to crop from command line. That way you may include the command inside an Applescript, or call the command directly from terminal.
You can install it following these instructions and then you crop all images inside a folder, given:

convert '*.jpg' -crop 120x120+10+5 thumbnail%03d.png

where 120x120 is the resulting size and 10+5 is the offset (10 pixels width and 5 pixels height).