How to make link thumbnail

It is an interesting script that automatically displays the linked page as a thumbnail when the mouse comes over the link string to the external site.

Examples and installation method are as follows.
An example is as follows.
http://lab.arc90.com/tools/linkthumb/

The code download and usage etc. are as follows.

Arc90 lab: tools: Link Thumbnail
http://lab.arc90.com/2006/07/link_thumbnail.php

Compatibility seems to be Internet Explorer 6.0 or higher, Mozilla Firefox 1.5 or higher, Apple Safari 2.0, Opera Version 8.51 or higher.

It is possible to distinguish only external sites properly and not to display thumbnails every time within your site.