Let me caution everyone about amateur interpretation of these images. Richie spotted the anomaly because it was dead-obvious - so dead-obvious that everyone else missed it because we were looking for things much more subtle. I don't see anything else in the imagery that is that obvious. We now have experts from several different companies looking at the raw sonar data to see if there's anything else there. Let's let them do their work. We've all seen what can happen when amateur imaginations run wild.
I second that. I threw the images together in 20 minutes on an older image processing program - hardly a professional assessment.
And as Ric points out, the viability of the smaller object actually being an engine, depends somewhat on how much, if any, of the wing/center section, the engine took with it when it separated from the aircraft.
Sometimes when it looks like a duck, walks like a duck, and quacks like a duck, it's just a rock.
That said, it does appear to be in the general ballpark of the size for a detached Electra engine.
The only way to find out, is to fund an expedition to go look at it.