I found this url : http://web-graphics.com/mtarchive/BubbleTooltips.html
This is what I am looking for, but how to add a link and an image to this this bubble? Any one got any idea?
Well, you can always re-use this code (might need a credit for the creator in the css code) and create your own bespoke background image. The link is associated with the text which triggers the tooltip - you can't click on the bubble itself