Easily resize multiple images at once. There are 5 types of resize: percentage, fixed width, fixed height, fixed size and fit to size. The resized images can be saved as JPEG or PNG.
It also has presets feature which allows you to save your favorite customizations for easy access.
Resizo is retina display and Mountain Lion ready.
You can download free trial version on http://www.vistanita.com/resizo/