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While it's impossible to confirm the photo's legitimacy, the worker's gloves and the sticker on the back of the case resemble what you'd find inside an iPhone factory, and it makes the image more likely to be real compared to some other recent purported leaks.
There's not a whole lot of information in the image, but as Cult of Mac points out, if this is the iPhone 7, it won't have the prominent plastic antenna bands that can be found crossing the backside of the iPhone 6S and 6S Plus.
The iPhone 7 is expected to be launched in September. Current rumors point to a full refresh of both hardware and software. Apple is expected to remove the headphone jack and replace it with another speaker, hinting at the possible addition of stereo audio. Other possibilities include a "pro" model with a camera that uses two lens for improved zoom.
Apple is also expected to launch a new, smaller iPhone at an event on its campus later this month on March 21. That phone will likely be as powerful as the current iPhone 6S, but in an iPhone 5S's body.