The closer spring gets, the more rumors we can expect to see about Samsung's next-Next Big Thing (TM). Today's alleged leak comes to us via Twitter, and let's not beat around the bush - this is almost certainly not the Galaxy S IV. We'll begin where any photo analysis starts: the pixels. Take a look at the USB port in particular.
If this picture is from Samsung, then it was made early enough in the design process that the graphic artist here knows his work will never see the light of day. To say nothing of the literally impossible lighting angles (which apparently results in identical reflections whether the device is standing up or lying down), the USB port is surrounded by a white glow and, judging by the front and rear shots, it is just a gash cut into the hardware.