Hello, i'm having a little problem with my YouTube videos and was wondering if anyone has ever come across the same thing.

Everything was working great... i've been uploading videos for a few months and they all look fine. No black borders. But during the last week big ugly black borders have appeared around the thumbnails in the tabs on my channel -- totally out of the blue.

The videos still look okay when you view them on their own individual pages -- there are no black borders then -- its only when you look at the thumbnails on my channel pages that you get the letterbox effect.

its very frustrating because they were perfectly okay for months, and now all of a sudden they looks lousy