Hey guys,
i have got subalbums in some albums. After clicking on such an album on the index page an overview of all subalbums is shown. In don't need that differentiation in subalbums, i just want to see a all of the folders pictures and the pictures of the subalbum as usual (same view as there were no subalbums). Is that possible? And how?

Of course it is possible. This is software after all. But no theme currently does this. Just curious, since you don't seem to want to make use of subalbums, why are you using them in the first place. If you just put all your images in the album folder instead of in subalbums you will get just what you describe.

I've ported my Coppermine gallery to ZenPhoto. The organisation of pictures in Coppermine were different, so i've created some subfolder, which didn't rely on the output in Coppermine - in Zen it does. Is it such complicated to change this?

It is much simpler to move the images. And, of course, that has to be done only once. Any code you have to morph this would execute each time a page is loaded.

But if you wish, review the themeing guide and Zenphoto functions descriptions, specially those with regard to the album and image objects. Change the next_album() loop to go through and display thumbnails for all the images in the album instead of the album thumb. (if you have nested subalbums within subalbums you will have to make this recursive.)

Note, though, that any sorting of images you select may look peculiar!