When the 16w20a snapshot announcement is opened in a slim browser window, the head at the beginning of the text suddenly fills the whole width of it. Tested with Chrome on Windows 7 and Opera on Android. It doesn't depend on width/height ratio (it also happens in landscape mode on mobile), but on the width in pixels.
Oh, it was "fixed" by removing it. That's sad. I liked a giant polar bear head more than no polar bear head.