Earlier quoted context omitted.
Could it also be someone with a stringray who intercepted Jeff's correspondence to and from Sanchez?
I suppose it could have been -- depending on the phones involved. MMS isn't encrypted AFAIK, but iMessage is. If you want exotic explanations, the images could have been recovered by Van Eck phreaking too, I suppose. More likely explanation is something like the geek squad scandal where someone with physical access to the device (e.g. cell phone repairman, personal assistant, hotel maid) copied the photos.
So now it comes out that Sanchez shared some photos (no mention of which) of her and Bezos with female friends, and some SFW photos with her brother. Additionally she backed up her phone to her computer, and her computer was backed up to her assistant's computer. It looks like a lot of people might have had access to the photos.