[Guilouz]

I just downloaded this mod. Very nice. I like the animated posters aswell. I have gone thru my library and manually added many. How can I add some newer posters that don't show up?

 When you enable Animated poster setting, animated artwork are automatically downloaded (it may take some times). If you want add manually, you need to use context menu and select 'Select animated artwork' option.  

I didn't realize there was such a setting. Is that new to this skin? Sounds great. Where exactly do you enable this? If I do not like it for some reason, can I just disable it and it will delete all the animated art without leaving the files behind? Is there a way to try it on a single title or two, before turning it on and having it download a lot of artwork before I have a sense for how it looks and works? 

It's not new, this setting is present from the beginning. You can enable it in Settings / Skin Settings / Artworks. Animated Artworks are not deleted when you disable this setting but they are stored in userdata / addon_data / script.module.metadatautils / animatedgif folder and you can delete them.