[Guilouz]

In the future will it be possible to manually add animated posters?  I also want some control over which ones are displayed as the quality of some of the automatically downloaded ones are quite poor, and also the searching seems to slow my slower clients down.  

Animated is powered by Skin Helper Service. You can choose them (if many animated artworks are available) with context menu on item or browse path to choose manually your own artworks.  

Hmm if I add one manually it doesn't work if I have the skin setting set to off - turning it to on means all the available animated artwork is downloaded i.e. there's no way to just add the ones I want 

This functionality working like that... If you enable animated posters, they are automatically downloaded by Skin Helper Service and after you can replace them.