First of all, it is not working correctly. I could see the image briefly for a second, but it disappears directly or is hidden. This may be a problem with my theme though.
The reason I give only one star is that it added another div section at the bottom of my page, that displays advertisement (an image-slider with a link to some page). See: wpsupersizedhiddenadd.jpg
Deleted it directly after seeing that, not the way to go. ;(