Last week we released Media Library Plus and Media Library Pro versions 3.0.8. Both plugins include the ability to regenerate thumbnails for the images in your library. If you have needed to regenerate thumbnails when you are switching to a new theme or when you need to add new thumbnail sizes to an existing theme you can now do that by file, folder or all of your images inside Media Library Plus or Media Library Plus Pro.
Oftentimes you might want also to use this new capability when using new thumbnail sizes to a plugin that uses images like MaxGalleria.
Regenerate thumbnails is one of those functions that you do not need until you need it. Then you need to go find a way to get it done. With MLP and MLPP you now have a powerful method for taking care of it.