Gulp.js - Automate and enhance your workflow
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Grunt - The Grunt ecosystem is huge and it's growing every day.
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats
Webpack - Webpack is a module bundler. Its main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.
Ralpha Image Resizer - High-speed image batch conversion tool