I suspect there is a way to do this using an image which is called from a folder on your machine and using the Image overlay. I'm not a programmer so I can't really help there, but I do something similar for a weather overlay I found a couple yrs ago. Something like this http://screencast.com/t/WRObWYlrRV each day the weather changes the icon is updated.Yes I want to overlay an image from ad url that constantly changing, like a weather stiker for example.