Of course there is no way of knowing if the image is legit, but assuming it is, here's a comparison.
093b is in the middle, while 093a is above and below it. Above shows a comparison with 093a sized up to be exactly the same length.
Below shows 093a sized up so it's several meters shorter than the 093b.
If the 093b image is legit, one can see various shape and layout differences. The sail is of different shape. The location of the sail in relation to the hull is somewhat different. The bow of the submarine appears to be slightly different too, though that's a bit hard to be sure about. The back hull line is different and less tapered, with a more pronounced end. And the whole horizontal tail appears to be of different size and shape. With the towed array sonar housing either missing or applied in a different, more compact housing. Or housed in another place.
093b is in the middle, while 093a is above and below it. Above shows a comparison with 093a sized up to be exactly the same length.
Below shows 093a sized up so it's several meters shorter than the 093b.
If the 093b image is legit, one can see various shape and layout differences. The sail is of different shape. The location of the sail in relation to the hull is somewhat different. The bow of the submarine appears to be slightly different too, though that's a bit hard to be sure about. The back hull line is different and less tapered, with a more pronounced end. And the whole horizontal tail appears to be of different size and shape. With the towed array sonar housing either missing or applied in a different, more compact housing. Or housed in another place.