At least I am not making the same mistakes again. New mistakes every try, but it looks like we are getting there now. After fixing the GIMP script and cropping the originals to a ratio of 2:3 it looks much better now. See http://www.usefilm.com/image/582547.html for the long story.
Picture details: Exposure 1/1250s, aperture 8.0 (fixed), focal length 500mm, ISO 1600, no flash, no tripod.
Like always. Comments, feedback, and ratings are highly appreciated.