I've recently seen some posts on tumblr that the originator calls "The Exposure Game". The "Player" agrees to post a few relatively innocent pictures for a limited period- usually six days. Once the post gets a predetermined number of reblogs, then more pictures are added. For each "level", more information and/or pictures are added to the post until the player has been completely exposed.
Perhaps an adaptation of this could help coerce your wife. For each day/week she refuses to post herself, one of her blackmail photos gets "leaked". As time goes on, more and more of her photos, videos, and personal info is let loose onto the net. Additional releases could be triggered by numbers of likes/reblogs/reposts in whatever venue you decide to use: 100 gets a faceless topless pic, 500 gets a full frontal faceless, 1000 gets a blurred BJ pic, etc. The details are, of course, up to you. If you want to limit it to KT, then a new poll or new thread, with votes as to what gets leaked next?
Short of posting the media yourself, or having her blackmailers do it, I'm not sure what else you might do to help move her along.