title: How to reduce the file size on JPEG images in batch (/Mac)?
body: <p>I have a list of .JPG files on a Mac. I want to export them to a format taking less than 500 kilobytes per image.
  I know how to do that using the Preview application one image at a time; but I want to be able to do the same in batch, meaning on several files at once. Is there a command line way to do it so I could write a script and run it in the terminal?
  Or some other way that I could use?</p>