According to an anonymous tipster, the image we have is a Best Buy flyer that is scheduled to run on July 28th (next Sunday), and the flyer clearly says "available Tuesday", which would be July 30th. The ad also confirms that the 16GB model of the tablet will cost $229, and confirms the display resolution at 1920x1200.
Also interesting is that the wallpaper on on the tablet in the flyer is the same that you would see as the default wallpaper on the Nexus 10. Usually, even incremental updates to Android means a new wallpaper on the launch device. Maybe Android 4.3 just isn't enough of an update to warrant any wallpaper change?