I think we will see these engines get much better in the next few years. AI research has gone on for ages with Turing doing some of the early work, but access to lots of processing power is accelerating things. I see lots of people saying they are 'dumb', but they can do a lot. They just lack that 'common sense' element that even some people struggle with. I would expect that people are developing knowledge bases of certain fundamental facts that the engines can use, so they don't give people too many fingers/noses/eyes in generated images.
This technology will create lots of challenges. We're already seeing it used to generate posts and replies here with peakd integrating it. It is a revolution and there will be casualties. I just hope that a lot of good can come out of it too.