I have written the french translation for your plugin (great work, I use it on every site I do now). I don't know how to send it to you so that you can integrate it in the plugin itself.
During the translation, I found a little bug. Some text are not translated because the text domain is not correctly specified :
on line 324 and 328, there is a trailing space in the textdomain name.
__("You can ....3.1+ only).", 'regenerate-thumbnails ')