It does seem unnatural, but I think it's unavoidable when you're showing images of a web interface inside another web interface (especially one with similar design cues). It's going to look strange either way, but it's a little more comfortable for the brain to keep the boundary when the inner image is tilted or perspective-shifted in some way.

The best answer would be an isolated image over black (or a lightbox effect) but alas their CMS probably doesn't support this kind of display.

BBC CMS does apparently do lightbox-ed galleries - http://pressitt.com/public/files/2009/12/17/713/OneDay-Light...

Uncanny valley of web design, anyone?

yeh that bugged me as well