Disable default WpodPress Image size uploads & define your own sizes.
These scripts disable the default WordPress image uploads and let your add your default sizes.
Be aware, that the execution of those scripts is time sensible, so timing is added to it. When using it with WPCodebox2, make sure you change the timing patameter in the options area of your script settings accordantly.
Also make sure, that you disable the generation of default images via Setting ==> Media by setting them to "0".