Unfortunately they're not pictures of the device, rather pictures taken using the device's camera.
About a week before the Nexus 7 was announced, pictures apparently captured using the device's camera showed up on Google-owned photo site Picasa. The photos in questions were attached to Google+ user Somit Bh's page and that the geo-location data indicated they were taken at Google Building 44 in Mountain View. Today, just days ahead of the supposed Nexus 10 launch, we're treated to a few snaps that were supposedly taken with the as-yet-unconfirmed tablet.
SlashGear reports that the Nexus 10 is listed as the camera used to capture several photos posted by Google's Vic Gundotra. Gundotra, who is Google's SVP of Engineering, appears to be on holidays at the moment and has uploaded at least two photos taken with the Nexus 10. Gundotra hasn't responded to the numerous comments mentioning the tablet but, with an event scheduled for Monday, there isn't long to wait for the juicy details.
Google is also rumored to be announcing a new 32GB Nexus 7 as well as a new Nexus smartphone from LG. That device will pack quad-core 1.5 GHz Qualcomm APQ8064 Snapdragon SoC, a 4.7-inch 1280 x 768 display, 2 GB of RAM, 8 GB of internal storage, an 8MP camera on the back, a 1.3MP camera on the front, and a 2100mAh battery.