Australia's MacFixit, the blog that got the photo, says the picture fits with the dimensions of a 4.7 inch screen - bigger than the current 4 inch screens on the iPhone 5, 5S and 5C, just as the rumors have suggested. People who want a massive 5.5 inch screen version ought to start worrying - we haven't seen any manufacturing photos of that device yet.
One obvious note: This thing is green. Don't worry, it's just a protective film. It won't be green in real life. Hopefully!
Here are some perspectives, first from AppleInsider:
While the part matches up with previous mock-up designs, it does feature something new in what looks to be a cutout in the shape of Apple's logo. With a protective green film obscuring most of the component, however, it's hard to tell whether the logo is actually cut out or merely polished. It's worth noting that the second-generation iPad mini, which some say inspired the iPhone 6 design, was found to have a similar feature when parts for the tablet first leaked in August 2013.
Like the dummies mentioned above, this shell features two distinct antenna breaks at the top and bottom, rounded corners, a circular cutout for the LED flash, and a larger overall size than the current iPhone 5s. The case appears to be covered in a protective plastic coating, but a bit of silver coloring is visible between the flash and camera cutouts, indicating that this could be for the sliver phone model.