Alright, after searching and working through some pages, and spending about 8 hours search in the web, I'll try to explain what I'm searchin for.
A customer want's the following:
There's a wordpress site which starts wich an image, below this image there's an image-slider with thumbnails of several galleries. When you're clicking on this thumbnail it links to the gallery page.
And when you're on this gallery page you have the following view:
On the left is a single image shown and on the right hand there's a gallery-view on which thumbnails related to this gallery are shown. When you're clicking on one of these thumbnails you get a new single-image on the left.
I hope I said it clearly. If there're any questions, you're welcome.
I also described the problem in my blog and there's also a picture for what I'm searchin for.