Generating thumbnails of the webpages visited on a client side

I developing an extension - firefox so with this extension i keep track of the pages the user visit开发者_开发知识库s and now what i want to do is, i want to be able to popup a thumbnail of the webpage when the user hovers the mouse over the link. i have done that using third party websites for generating thumbnials such as http://images.websnapr.com. I was wondering if there was anyway i could do it on clientside without having to use third party website.

Any suggestions?

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You can also just use firefox's own canvas. Look here for an example :

http://fixunix.com/mozilla/408090-firefox-page-capture-image-need-minor-tweaks-autochosen.html

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i would recommend you to look at the screengrab extension, which does just that: https://addons.mozilla.org/en-US/firefox/addon/1146

(i think it uses java as underlying layer)