I don’t blame Cruz for the pic. I’ve seen no evidence that he knew in advance, and he handled the nude pic like he handles attacks on himself, by ignoring it until the pic became a distraction. That is the correct approach, based on what works in a political campaign.
I do consider the pic both an attack and sleazy. At least in the short term, the attack looks like it was meant to help Cruz. I suspect the attack was meant more to stop Trump, so that the establishment could pic the nominee - and the nominee was not intended to be Cruz either.
The simple fact that the ad appeared is evidence that things are not what they seem here. Don't you find it strange that the Melania ad ran in a state that Cruz was projected to win big? Why waste the money and risk any backlash by going after Trumps wife if he was already going to win big?
Here is what I think happened ... Cruz knew the NE story was coming out ... and the Melania ad was a preemptive strike so Cruz could frame the NE story as retaliation.
Now if you have a better explanation of the Melania ad then go for it ...