Wikis are harder to deal with. It's possible that a Cease and Desist was sent to Fandom.com or to the old founders of MA, but it lingers in an inbox somewhere or to the bemusement of an individual who doesn't have the authority to remove the image. They need to go through a deletion vote and MA claims fair use over the image (and all publicity images).
Episodes have been leaked before. Not Star Trek, as far as I know, but I recall alot of mistakes in the early days of wikis and on demand television (HBO's Deadwood coming out a week early, some episodes of Spartacus released out of order). The routine back then was to shrug and add the info, but there wasn't a big concerted effort to pull the episode and hide all of its reveals.
Then again, a full work print of Wolverine Origins was released online months early, but wasn't included in most, if any, wikis because it wasn't the final film. The Japanese version of this episode falls into this category, perhaps, if only because it's release was covered up so quickly and we are just given the usual spoiler-filled crumbs. At any given time, upwards of three dozen people have seen next week's episode (or even up to the finale), and not all of them have NDAs. It's just a subset of the millions who watch who go on within seconds to update the wiki.
Given that no one has updated MA as of this writing (and MA does only include officially released or published material, that promo pic aside), I'm guessing the episode hasn't been disseminated, and the Japanese Amazonians never managed to download and "redistribute" the episode. This confirms my suspicions a couple nights ago when attempting to... research the episode. No evidence of an unofficial release in any of the usual locations, or hints of its existence in the wild.
But, again, three dozen people have seen it anyway, so the plot synopsis would be out there for those willing and able to procure it.
