Using the JavaScript In Retrobatch
With Retrobatch Pro 1.2 or later, you can write JavaScript to process your images in two ways:
Using the JavaScript Node
With this technique, you can drag and drop the JavaScript node into your canvas and then write your custom JavaScript code in the inspector. This is a good solution if you have a quick idea for processing your images which doesn't require much code. Documentation for the JavaScript node is available online.
Writing Plug-In Nodes in JavaScript
If your idea is more involved or you would like to distribute your plugin to other users (or maybe you'd like to use a text editor outside of Retrobatch), then writing a custom Plug-In node in JavaScript is the way to go. Documentation for writing these plugins, as well as samples, are available on the Retrobatch JavaScript API site.