In fact, I'm going to quote a user from RangerCrew who proved it fake:
"I'm gonna call bull on the ToQ Z. Toei is hard about spoilers down to not allowing the cast to post pictures of themselves in any costumes during filming for their blogs so I'd find it so incredibly odd that they'd be fine with Kengo posting that ToQ-Z cookie if that was actually already planned for the show. And how odd that only after that picture was posted that this picture of the suit comes about? Not to mention nobody even knows where it came from. Almost nothing is found out from an online image, it's almost exclusively scans from magazines. That's not to mention the flaws in the suit liking the ToQ 6 helmet looking shoddily put on a regular suit. The rail lines around the number being incorrect, the 7 being shoddily added on, the glare on the suit being so much more vivid on his than the others."
When someone replied that Japanese fans saw a purple ToQger on set:
"You mean the fans that were taking pictures of the filming? The ones who said they SAW it, but just didn't get a picture of it? Imagine that. And if we're going by the picture we have Purple's fight would be in the Toei Quarry which is off the beaten trail and their property so no cameras or spectators. People have been wanting a Purple Ranger since before the show began and have been jumping at any chance to claim it as so. Like I said, if Toei is going to do something they're either going to release it themselves (Via Magazine Scans), or they're not going to release it ahead of time. They're not just going to let the actor spill the beans via a cookie on his blog.
And the most damning evidence, do you honestly believe that fine as hell Zed would have his roll call pose just be a repeat of ToQ-6's awkward 6 fingers? Oh please. You know he'd have the most magnificent pose out there."
And I completely agree with him - the image is clearly fake, quite likely a photoshop. Therefore its authenticity is in question as well as the information it allegedly "proves".