Can't make out too much of these images.
Pieces seem pretty big.
However China would probably not release this information unless they were certain. They certainly would have the means to have a much more detailed look before releasing these low res photos.
Direction is right. Unlikely plane turned around and overflew land. Cell phones are often left on, and do work just fine at cruise levels. Certainly good enough to be tagged by network. Certainly good enough for SMS or data. And sometimes good enough for voice. If it had reversed course and pax concerned, someone would have got a message out.
All the stuff to the west is confusion, random "noise" and some rumors.