If you are looking for a plugin that can create thumbnails automatically and is clickable for enlargement of the image, you should take a look at this:
http://iprice-web.ru/en/products/smartresizer (It's free)
Please take a look at
ertmania.dk too see how it works.
You can get in touch with me on twitter:
twitter.com/ertmaniadk in English :)
Thanks for your information. i'm also looking for a plugin like this.