This plugin attaches a tooltip with a screenshot of the linktarget to every external link.
Activate the plugin and change the setting of 'Show screenshots for all external links?' to 'No'
When you write a new post, change to the source view and to your link code e.g.
bla bla bla <a href="http://www.zyblog.de">External link to Zyblog</a> bla bla bla
is changed to
bla bla bla <a href="http://www.zyblog.de" size="M">External link to Zyblog</a> bla bla bla
Allowed values to mark your links are 'T', 'S', 'M', 'L'
A size attribute added by hand will override the thumbnail size settings done on the plugin settings page.
Most of the screenshotservices show default pictures, when the screenshots must be generated or could not be generated.
For this plugin the service of seekXL Snapr allows you to use your own picture as a replacement for the default picture. That way is is possible to integrate the tooltips into your own design.