[Plugin: NGGallery] problem with absolute path to slideshow

I installed NextGenGallery on a new site, mainly to run a slideshow in a sidebar widget. Because of a special internal DNS setup at the clients house, I need to specify absolute paths to some images, and also to this slideshow. But when I specify the absolute path http://www.domain.com/wp-content/gallery/images in the gallery settings, the slideshow pictures turn up at
http://www.domain.com/http://www.domain.com/wp-content/gallery/images/example.jpg (sic!)

Any ideas to why this is happening?