Thanks for this plugin, it saved me a lot of times but I suggest some features:
- Not really know why set new sizes for generating only through Appearences > Media. Why not just add this options such Aditional Image Sizes plugin, works with function add_image_size.
- Can be able to exclude old image files based on size or name. This saves a lot of server space.
I think this covers things that most people want, I can help on localization later (the only thing I can do for now on PHP) :)