[pkscout]

If I listen to radio, As will still download images and create a Artist folder on my custom path and save them in there without the extrafanart folder, right?

There is a setting in AS to disable the extrafanart folder.  You need to go into the AS settings and find Storage > Use extranfanart folder.  Disable that and then, yes, AS will do as you've described.
 

If you digging in the code right know I would like to add a request, I'm sure I'm in the minority but hey, I don't care about the extra info, all I want is the slideshow. So if you could add a option to disable the artist info search, witch will bring down the api request, or just let as not create the info folder with the nfos, would be great.

You can already do that.  There are sections in the settings for Album Info, Artist Bio, and Similar Artists. In each of those sections you can disable the download of that information for each site that provides it. It won't actually cut down on the API calls much, as the data for those is usually in the same file as the one that has all the images.

AS still has to create the information folder, because the files that have the list of images is cached as well as the database of already downloaded images (these two things do more to limit the API calls than anything else).  So there's no way to avoid have information folders.  The new version of AS does let you store the information folders separate from the image folders (in the Storage section of settings), so if you do that your image directories will be clean at least.  If you're not trying to share the AS stuff with two Kodi setups, you can probably just set the information files to be stored in the addon_data folder.  Then you'll basically never see them.