Just discovered thanks to a comment, a bookmarklet that adds thumbshots.org thumbnails to any link on any page: Link Preview by Globefeed.com (basically a Google maps mash-up service.)
Before and after using the Link Preview bookmarklet.
To always have thumbnails on some sites, I know it's possible using the Firefox Bettersearch extension for Google web and News search results, Greasmonkey scripts like Google Thumbnails or other preview scripts. Greasmonkey scripts are specially nice because you can set them to work exactly only where you want.
About thumbnails, lab.arc90 have a great script called Link Thumbnail that shows thumbnails when hovering over a link. (I've added some here as example.)
I thought it would be nice to have them on some of my list posts, like here or here, so you can have a quick glimpse without the need to navigating away... Or is it too much clutter?
Marjolein Hoekstra's added it globally to her blog, check it out. :)
Related: Creating or using thumbshots online. I've added some more tools at the bottom.
Category: bookmarklet 
tags:Thumbshot Thumbnail Web Tools
Labels: bookmarklet, thumbshots
