Above two images are reportedly of Lumia 1330 / Lumia 1335 back cover and are leaked by the same person who has leaked below images of the Lumia 1330 back. The second image has a Lumia 535 placed in the cover and show how bigger Lumia 1330 will be in real-life. Also, note the Microsoft branding.
Now, if we consider the first image leak for Lumia 1330, that had it with a batch of other phones, things look quite consistent.