Looking for this option I discovered it under System>Skin>General>TV Shows section. Shouldn't it be under System>Video>Library? You may answer "it's a skin option" then I say "shouldn't be the skin to tell to xbmc that is capable of managing both banners and posters for tv show, then xbmc decides to blur or not that option?".
The setting is actually in the scraper as to which it fetches. The skin setting you've discovered is to try and align what the skin displays with what the user may have decided to scrape. Different scrapers (or different folders using the same scraper but different settings) can feed back different images.
Now that video art is in the texturecache, it is now feasible to implement fetching both posters and banners, and thus allowing the skin to show the image they prefer. Obviously a chunk of code needs writing for this, but the groundwork is now done.
Cheers,
Jonathan
Got it, I had not considered the fact that the "prefer posters" choice begins from the scraper. Thanks for the clarification.