The conspiracy is that either she is dead, divorcing, or critically unwell and that the Palace is hiding it. Kate has not been seen since December and the circumstances surrounding that are unusual. That being said, there are rumors and blind items out there that are very wild, but a few have been whispered for years. The man married to the daughter of the QEII's cousin, was found shot dead. The UK press twisted themselves into pretzels in an attempt to make it seem as if it was natural causes. It was not. This man was a former lover of Kate's sister and supposedly close to the family.
This photo in particular, was not given to the press as normal. Media organizations require proof regarding certain alteration specifics. This is not a photograph that has just been 'retouched'. I can tell you the head has been taken from a magazine cover, the lower half has been altered, the wedding ring was missing (hands added came from somewhere else), the children have been placed in a variety of odd ways. The work done to the photo is obvious and sloppy. Now, they have done some sloppy edits before but something about how this photo was presented did not go through typical channels. The image of Kate in this photograph also does not match to one that was taken by paps a few days prior - one the Palace thought so unflattering, they ordered UK media to hide it. Today the UK media was allowed to pap a photo of someone in a vehicle purported to be her, but only the back of her head.
No one knows what is wrong with Kate, some people have alluded, and it's not good. It is no way for the lady to be treated, and most people just want her to be safe and ok.