In addition to reasons i offered earlier for the matter of why aren't we seeing more J15 already - here is another one. Possibly the main reason, really.
It all goes under the assumption that Henri K's projections about number of certified pilots are correct. (which they may not be)
Back in 2017 he did this projection.
In it he supposed that in 2017 there were 29 to 36 pilots certified for j15. And he further projected 39 to 56 pilots for 2019.
Recently, he slightly changed his 2019 projection to 45 to 55 pilots.
Now, certified pilots may not include the initial test pilots that flew the prototypes. Indeed, his 2017 table says in 2012 there were 0 certified pilots, so it would appear he is only counting the pilots that graduated from the school for carrier pilots.
Now, how many pilots should there be per carrier? The general rule of thumb in every air force is - the smaller the air force, the more pilots per plane are needed. Some tiny airforces went with 2 pilots per fighter jet seat. USAF, being a huge air force, has that ratio at 1.3 pilots per fighter jet seat. USN carrier squadrons have that ratio at 1.5 pilots per seat, as far as i could find.
That's for roughly 45+ fighter jets on a carrier. For a smaller force of, say, 24 fighters, the ratio may need to be even slightly bigger.
While we have those test pilots, that may not be counted within the certified pilot pool, those probably do have their hands full with various other development units. Further J15 development, twin seater variant, EW variant, catapult demonstrator, etc. We've seen all those subvariants of J15 to exist.
Now, since Liaoning can operate 24 planes, in order for it to use them to their fullest potential, at least 36 pilots might be needed. Which would leave, according to Henri K., 9 to 19 pilots. But some of those pilots are almost certainly doing their share to help teach new generation of pilots. How many would that be is hard to say. Could be 5, could be 10. Or even more.
But even with just, say, 6 more pilots doing the training of cadets (probably some of the first gen test pilots, not within this certification estimate, may also be involved in training) we would be looking at 3 to 13 pilots available. Which, with the minimal 1.5 ratio, means just 2 to 8 J15 planes being available for the second carrier. If 10 certified pilots are helping with the training, possibly on twin seater J15s that we haven't seen many images of, then 0 to 9 new certified pilots might be free for the second carrier air wing. Meaning just up to 6, and possibly none, new J15s could have pilots available for them.
So, IF the above does hold some merit, it's no wonder we haven't seen any new J15 images. As there probably aren't many new J15 out there. Why build 24 planes only to have them wait? By the same logic, PLAN may not be in a rush to get the second carrier commissioned as there's no pilots to start getting accustomed to it. (though this line of reasoning is less solid than for J15, as crew could get trained on Liaoning)
Of course, it all depends on how accurate those pilot certification number estimates are.