1.) It's a photoshop picture
2.) It's a FC-31 upgrading to an improved WS-10 engine.
3.) It's a J-20 downgrading to an improved WS-10 engine, because the WS-15 engine production cannot keep up with the airframe production, but PLAAF's need for the J-20 is extremely urgent.
The J-20 with WS-10X could be used to train new pilot for subsonic maneuvers, while the J-20 with WS-15 used for Supersonic maneuvers.
It's a clunky solution, but doable, for the shortage of WS-15 engine problem, which I suspect China won't be fully mass produced it at the rate of 50-100/year, for another 2-3 years.
#2 is mostly likely. FC-31 is installed with the Russian RD-33 engine, which is a low thrust, smokey, low tech engine from the F-4 Phantom's J79 engine era of the 1960's. If FC-31 is sold with the RD-33 engine, no one will be fooled that this plane is a high tech 5-Gen. plane.
Not even the African Air Forces will be fooled. So FC-31 must upgrade its engine to have a prayer of hope. Remember, the FC-31, right from the start, is a junk project designed to fool the PLAAF into buying it, using the Internet Forums.
The FC-31 is undoubtedly inferior to the J-20 but I wouldn't necessarily classify it as "junk". It still has decent prospects of becoming the PLANAF's new carrier fighter ...
Why not? The J-20 was never designed to be a carrier fighter given its weight class. It is optimized for ground based air superiority, not an asset used for naval aviation. The FC-31 is ideal for this role (maybe bc they ripped off the F-35).
Why not? It's a piece of junk from top to bottom, front to rear, and left to right. it is this kind of mindless cheap copy, cheap knock off that give Chinese manufacturers a bad name.